# vim:et sts=4 sw=4
#
# ibus-table-setup - Setup UI for ibus-table
#
# Copyright (c) 2008-2010 Peng Huang <shawn.p.huang@gmail.com>
# Copyright (c) 2010 BYVoid <byvoid1@gmail.com>
# Copyright (c) 2012 Ma Xiaojun <damage3025@gmail.com>
# Copyright (c) 2012 mozbugbox <mozbugbox@yahoo.com.au>
# Copyright (c) 2014-2022 Mike FABIAN <mfabian@redhat.com>
#
# This library is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 2.1 of the License, or
# (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this library.  If not, see <http://www.gnu.org/licenses/>

'''
The setup tool for ibus-table.
'''

from typing import Union
from typing import Any
from typing import Dict
from typing import List
from typing import Tuple
from typing import Optional
from types import FrameType
import sys
import os
import re
import html
import signal
import argparse
import locale
import copy
import logging
import logging.handlers
import dbus # type: ignore
import dbus.service # type: ignore

# pylint: disable=wrong-import-position
from gi import require_version # type: ignore
require_version('Gio', '2.0')
from gi.repository import Gio # type: ignore
require_version('GLib', '2.0')
from gi.repository import GLib

# set_prgname before importing other modules to show the name in warning
# messages when import modules are failed. E.g. Gtk.
GLib.set_application_name('IBus Table Preferences')
# This makes gnome-shell load the .desktop file when running under Wayland:
GLib.set_prgname('ibus-setup-table')

require_version('Gdk', '3.0')
from gi.repository import Gdk
require_version('Gtk', '3.0')
from gi.repository import Gtk
require_version('Pango', '1.0')
from gi.repository import Pango
require_version('IBus', '1.0')
from gi.repository import IBus
# pylint: enable=wrong-import-position

# pylint: disable=import-error
sys.path = [sys.path[0]+'/../engine'] + sys.path
import tabsqlitedb
import ibus_table_location
import it_util
import it_sound
# pylint: enable=import-error

from i18n import N_, _, init as i18n_init

LOGGER = logging.getLogger('ibus-table')

GLIB_MAIN_LOOP: Optional[GLib.MainLoop] = None

GTK_VERSION = (Gtk.get_major_version(),
               Gtk.get_minor_version(),
               Gtk.get_micro_version())

PARSER = argparse.ArgumentParser(
    description='ibus-table setup tool')
PARSER.add_argument(
    '-n', '--engine-name',
    action='store',
    type=str,
    dest='engine_name',
    default='',
    help=('Set the name of the engine, for example “table:cangjie3” '
          'or just “cangjie3”. Default: "%(default)s". '
          'If this option is not used, the value of the environment '
          'variable IBUS_ENGINE_NAME is tried instead. '
          'If the variable IBUS_ENGINE_NAME is also not set or empty, '
          'this help is printed.'))
PARSER.add_argument(
    '-q', '--no-debug',
    action='store_true',
    default=False,
    help=('Do not write log file '
          '~/.cache/ibus-table/setup-debug.log, '
          'default: %(default)s'))

_ARGS = PARSER.parse_args()

# Keep some translatable strings which are not used anymore here
# so that the translations which have been done already are not lost.
# I might want to use these strings again later.
UNUSED_OLD_TRANSLATIONS = [
    N_('Initial state'),
    N_('Direct input'),
    N_('Table input'),
]

class SetupUI(Gtk.Window): # type: ignore
    '''
    User interface of the setup tool
    '''
    def __init__( # pylint: disable=too-many-statements
            self, engine_name: str = '') -> None:
        self._engine_name = engine_name
        Gtk.Window.__init__(
            self,
            title='码 IBus Table '
            + self._engine_name + ' '
            + _('Preferences'))
        Gtk.Window.set_default_icon_from_file(
            os.path.join(
                ibus_table_location.data(), 'icons', 'ibus-table.svg'))
        self.set_name('IBusTablePreferences')
        self.set_modal(True)
        style_provider = Gtk.CssProvider()
        style_provider.load_from_data(
            b'''
            #IBusTablePreferences {
            }
            row { /* This is for listbox rows */
                border-style: groove;
                border-width: 0.05px;
            }
            ''')
        Gtk.StyleContext.add_provider_for_screen(
            Gdk.Screen.get_default(),
            style_provider,
            Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION)

        database_filename = os.path.join(
            os.path.join(ibus_table_location.data(), 'tables'),
            self._engine_name + '.db')
        if not os.path.exists(database_filename):
            LOGGER.error('Cannot open database %s', database_filename)
            sys.exit(1)
        user_database_filename = os.path.basename(database_filename).replace(
            '.db', '-user.db')
        self.tabsqlitedb = tabsqlitedb.TabSqliteDb(
            filename=database_filename,
            user_db=user_database_filename,
            create_database=False)

        self.__is_db_chinese = False
        self.__is_cjk = False
        languages_str = self.tabsqlitedb.ime_properties.get('languages')
        if languages_str:
            languages = languages_str.split(',')
            for language in languages:
                if language.strip().startswith('zh'):
                    self.__is_db_chinese = True
                for lang in ['zh', 'ja', 'ko']:
                    if language.strip().startswith(lang):
                        self.__is_cjk = True
        self.__user_can_define_phrase = False
        user_can_define_phrase = self.tabsqlitedb.ime_properties.get(
            'user_can_define_phrase')
        if user_can_define_phrase:
            self.__user_can_define_phrase = (
                user_can_define_phrase.lower() == 'true')
        self.__rules = self.tabsqlitedb.ime_properties.get('rules')

        self._gsettings = Gio.Settings(
            schema='org.freedesktop.ibus.engine.table',
            path=f'/org/freedesktop/ibus/engine/table/{self._engine_name}/')
        self._fill_settings_dict()
        self.set_title(
            '码 IBus Table '
            + self._engine_name + ' '
            + _('Preferences'))

        self.connect('destroy-event', self.__class__._on_destroy_event)
        self.connect('delete-event', self.__class__._on_delete_event)

        self._main_container = Gtk.Box()
        self._main_container.set_orientation(Gtk.Orientation.VERTICAL)
        self._main_container.set_spacing(0)
        self.add(self._main_container) # pylint: disable=no-member
        self._notebook = Gtk.Notebook()
        self._notebook.set_visible(True)
        self._notebook.set_can_focus(False)
        self._notebook.set_scrollable(True)
        self._notebook.set_hexpand(True)
        self._notebook.set_vexpand(True)
        self._main_container.pack_start(self._notebook, True, True, 0)
        self._dialog_action_area = Gtk.Box()
        self._dialog_action_area.set_orientation(Gtk.Orientation.HORIZONTAL)
        self._dialog_action_area.set_visible(True)
        self._dialog_action_area.set_can_focus(False)
        self._dialog_action_area.set_hexpand(True)
        self._dialog_action_area.set_vexpand(False)
        self._main_container.pack_end(self._dialog_action_area, True, True, 0)
        self._about_button = Gtk.Button(label=_('About'))
        self._about_button.set_hexpand(True)
        self._about_button.connect('clicked', self.__class__._on_about_button_clicked)
        self._dialog_action_area.add(self._about_button)
        self._restore_all_defaults_button = Gtk.Button()
        self._restore_all_defaults_button.set_hexpand(True)
        self._restore_all_defaults_button_label = Gtk.Label()
        self._restore_all_defaults_button_label.set_text(
            _('Restore all defaults'))
        self._restore_all_defaults_button.add(
            self._restore_all_defaults_button_label)
        self._restore_all_defaults_button.connect(
            'clicked', self._on_restore_all_defaults_button_clicked)
        self._dialog_action_area.add(self._restore_all_defaults_button)
        self._close_button = Gtk.Button()
        self._close_button.set_hexpand(True)
        self._close_button_label = Gtk.Label()
        self._close_button_label.set_text_with_mnemonic(_('_Close'))
        self._close_button.add(self._close_button_label)
        self._close_button.connect('clicked', self.__class__._on_close_clicked)
        self._dialog_action_area.add(self._close_button)

        grid_border_width = 10
        grid_row_spacing = 10
        grid_column_spacing = 10

        self._options_grid = Gtk.Grid()
        self._options_grid.set_visible(True)
        self._options_grid.set_can_focus(False)
        self._options_grid.set_border_width(grid_border_width)
        self._options_grid.set_row_spacing(grid_row_spacing)
        self._options_grid.set_column_spacing(grid_column_spacing)
        self._options_grid.set_row_homogeneous(False)
        self._options_grid.set_column_homogeneous(True)
        self._options_grid.set_hexpand(True)
        self._options_grid.set_vexpand(False)
        self._options_label = Gtk.Label()
        # Translators: This is the label of a tab in the setup tool.
        # Here the user can set up some options which influence the
        # behaviour of ibus-table.
        self._options_label.set_text(_('Settings'))

        self._options_details_grid = Gtk.Grid()
        self._options_details_grid.set_visible(True)
        self._options_details_grid.set_can_focus(False)
        self._options_details_grid.set_border_width(grid_border_width)
        self._options_details_grid.set_row_spacing(grid_row_spacing)
        self._options_details_grid.set_column_spacing(grid_column_spacing)
        self._options_details_grid.set_row_homogeneous(False)
        self._options_details_grid.set_column_homogeneous(True)
        self._options_details_grid.set_hexpand(True)
        self._options_details_grid.set_vexpand(False)
        self._options_details_label = Gtk.Label()
        # Translators: This is the label of a tab in the setup tool.
        # Here the user can set up some more advanced options.
        self._options_details_label.set_text(_('Details'))

        self._keybindings_vbox = Gtk.Box()
        self._keybindings_vbox.set_orientation(Gtk.Orientation.VERTICAL)
        self._keybindings_vbox.set_spacing(0)
        margin = 10
        self._keybindings_vbox.set_margin_start(margin)
        self._keybindings_vbox.set_margin_end(margin)
        self._keybindings_vbox.set_margin_top(margin)
        self._keybindings_vbox.set_margin_bottom(margin)
        self._keybindings_label = Gtk.Label()
        # Translators: This is the label of a tab in the setup tool.
        # Here the user can customize the key bindings to execute
        # certain commands of ibus-table. For example which key to use
        # to commit, which key to use to move to the next candidate
        # etc...
        self._keybindings_label.set_text(_('Key bindings'))

        self._input_method_menu_grid = Gtk.Grid()
        self._input_method_menu_grid.set_visible(True)
        self._input_method_menu_grid.set_can_focus(False)
        self._input_method_menu_grid.set_border_width(grid_border_width)
        self._input_method_menu_grid.set_row_spacing(grid_row_spacing)
        self._input_method_menu_grid.set_column_spacing(grid_column_spacing)
        self._input_method_menu_grid.set_row_homogeneous(False)
        self._input_method_menu_grid.set_column_homogeneous(True)
        self._input_method_menu_grid.set_hexpand(True)
        self._input_method_menu_grid.set_vexpand(False)
        self._input_method_menu_label = Gtk.Label()
        self._input_method_menu_label.set_text(_('Menu Items'))

        self._notebook.append_page(
            self._options_grid,
            self._options_label)
        self._notebook.append_page(
            self._options_details_grid,
            self._options_details_label)
        self._notebook.append_page(
            self._keybindings_vbox,
            self._keybindings_label)
        self._notebook.append_page(
            self._input_method_menu_grid,
            self._input_method_menu_label)

        _options_grid_row = -1

        self._remember_input_mode_label = Gtk.Label()
        self._remember_input_mode_label.set_text(
            # Translators: A combobox to choose whether the input mode
            # (“Direct input” or “Table input”) should be remembered
            # or whether ibus-table should always use “Table input” by
            # default after a restart.
            _('Remember input mode'))
        self._remember_input_mode_label.set_tooltip_text(
            # Translators: A tooltip for the label of the combobox to
            # choose whether the input mode (“Direct input” or “Table
            # input”) should be remembered or whether ibus-table
            # should always use “Table input” by default after a
            # restart.
            _('Whether the last used input mode should be remembered '
              'or whether ibus-table should start in “Table mode” '
              'by default after a restart. There are two input modes: '
              '“Table input” means the input method is on. '
              '“Direct input” is almost the same as if the '
              'input method were off, i.e. not used at all, most '
              'characters just get passed to the application. '
              'But some conversion between fullwidth and '
              'halfwidth may still happen in direct input mode.'))
        self._remember_input_mode_label.set_xalign(0)
        self._remember_input_mode_combobox = Gtk.ComboBox()
        self._remember_input_mode_store = Gtk.ListStore(str, bool)
        self._remember_input_mode_store.append(
            [_('No'), False])
        self._remember_input_mode_store.append(
            [_('Yes'), True])
        self._remember_input_mode_combobox.set_model(
            self._remember_input_mode_store)
        renderer_text = Gtk.CellRendererText()
        self._remember_input_mode_combobox.pack_start(
            renderer_text, True)
        self._remember_input_mode_combobox.add_attribute(
            renderer_text, "text", 0)
        for index, item in enumerate(self._remember_input_mode_store):
            if self._settings_dict['rememberinputmode']['user'] == item[1]:
                self._remember_input_mode_combobox.set_active(index)
        self._remember_input_mode_combobox.connect(
            "changed",
            self._on_remember_input_mode_combobox_changed)
        _options_grid_row += 1
        self._options_grid.attach(
            self._remember_input_mode_label, 0, _options_grid_row, 1, 1)
        self._options_grid.attach(
            self._remember_input_mode_combobox, 1, _options_grid_row, 1, 1)

        self._chinese_mode_label = Gtk.Label()
        self._chinese_mode_label.set_text(
            # Translators: A combobox to choose the variant of
            # Chinese which should be preferred.
            _('Chinese mode:'))
        self._chinese_mode_label.set_tooltip_text(
            # Translators: A tooltip for the label of the combobox to
            # choose which variant of Chinese should be preferred.
            _('“Simplified Chinese” shows only characters \n'
              'used in simplified Chinese. “Traditional Chinese”\n'
              'shows only characters used in traditional Chinese.\n'
              '“Simplified Chinese before traditional” shows all\n'
              'characters but puts the simplified characters higher\n'
              'up in the candidate list. “Traditional Chinese before\n'
              'simplified” puts the traditional characters higher up\n'
              'in the candidate list. “All characters” just shows all\n'
              'matches without any particular filtering on traditional\n'
              'versus simplified Chinese.'))
        self._chinese_mode_label.set_xalign(0)
        self._chinese_mode_combobox = Gtk.ComboBox()
        self._chinese_mode_store = Gtk.ListStore(str, int)
        self._chinese_mode_store.append(
            # Translators: This is the setting to use only
            # simplified Chinese
            [_('Simplified Chinese'), 0])
        self._chinese_mode_store.append(
            # Translators: This is the setting to use only
            # traditional Chinese
            [_('Traditional Chinese'), 1])
        self._chinese_mode_store.append(
            # Translators: This is the setting to use both
            # simplified and traditional Chinese but prefer
            # simplified Chinese
            [_('Simplified Chinese before traditional'), 2])
        self._chinese_mode_store.append(
            # Translators: This is the setting to use both
            # simplified and traditional Chinese but prefer
            # traditional Chinese
            [_('Traditional Chinese before simplified'), 3])
        self._chinese_mode_store.append(
            # Translators: This is the setting to use both
            # simplified and traditional Chinese in no
            # particular order
            [_('All Chinese characters'), 4])
        self._chinese_mode_combobox.set_model(
            self._chinese_mode_store)
        renderer_text = Gtk.CellRendererText()
        self._chinese_mode_combobox.pack_start(
            renderer_text, True)
        self._chinese_mode_combobox.add_attribute(
            renderer_text, "text", 0)
        for index, item in enumerate(self._chinese_mode_store):
            if self._settings_dict['chinesemode']['user'] == item[1]:
                self._chinese_mode_combobox.set_active(index)
        self._chinese_mode_combobox.connect(
            "changed",
            self._on_chinese_mode_combobox_changed)
        if self.__is_db_chinese:
            _options_grid_row += 1
            self._options_grid.attach(
                self._chinese_mode_label, 0, _options_grid_row, 1, 1)
            self._options_grid.attach(
                self._chinese_mode_combobox, 1, _options_grid_row, 1, 1)

        self._table_full_width_letter_mode_label = Gtk.Label()
        self._table_full_width_letter_mode_label.set_text(
            # Translators: A combobox to choose the letter width
            # while in “Table input” mode.
            _('Table input letter width:'))
        self._table_full_width_letter_mode_label.set_tooltip_text(
            # Translators: A tooltip for the label of the combobox to
            # choose the letter width while in “Table input” mode.
            _('Whether to use fullwidth or halfwidth\n'
              'letters in table input mode.'))
        self._table_full_width_letter_mode_label.set_xalign(0)
        self._table_full_width_letter_mode_combobox = Gtk.ComboBox()
        self._table_full_width_letter_mode_store = Gtk.ListStore(str, bool)
        self._table_full_width_letter_mode_store.append(
            # Translators: This is the mode to use half width letters
            # while in “Table input” mode.
            [_('Half'), False])
        self._table_full_width_letter_mode_store.append(
            # Translators: This is the mode to use full width letters
            # while in “Table input” mode.
            [_('Full'), True])
        self._table_full_width_letter_mode_combobox.set_model(
            self._table_full_width_letter_mode_store)
        renderer_text = Gtk.CellRendererText()
        self._table_full_width_letter_mode_combobox.pack_start(
            renderer_text, True)
        self._table_full_width_letter_mode_combobox.add_attribute(
            renderer_text, "text", 0)
        for index, item in enumerate(self._table_full_width_letter_mode_store):
            if self._settings_dict['tabdeffullwidthletter']['user'] == item[1]:
                self._table_full_width_letter_mode_combobox.set_active(index)
        self._table_full_width_letter_mode_combobox.connect(
            "changed",
            self._on_table_full_width_letter_mode_combobox_changed)
        if self.__is_cjk:
            _options_grid_row += 1
            self._options_grid.attach(
                self._table_full_width_letter_mode_label,
                0, _options_grid_row, 1, 1)
            self._options_grid.attach(
                self._table_full_width_letter_mode_combobox,
                1, _options_grid_row, 1, 1)

        self._table_full_width_punct_mode_label = Gtk.Label()
        self._table_full_width_punct_mode_label.set_text(
            # Translators: A combobox to choose the punctuation width
            # while in “Table input” mode.
            _('Table input punctuation width:'))
        self._table_full_width_punct_mode_label.set_tooltip_text(
            # Translators: A tooltip for the label of the combobox to
            # choose the punctuation width while in “Table input” mode.
            _('Whether to use fullwidth or halfwidth\n'
              'punctuation in table input mode.'))
        self._table_full_width_punct_mode_label.set_xalign(0)
        self._table_full_width_punct_mode_combobox = Gtk.ComboBox()
        self._table_full_width_punct_mode_store = Gtk.ListStore(
            str, bool)
        self._table_full_width_punct_mode_store.append(
            # Translators: This is the mode to use half width punctuation
            # while in “Table input” mode.
            [_('Half'), False])
        self._table_full_width_punct_mode_store.append(
            # Translators: This is the mode to use full width punctuation
            # while in “Table input” mode.
            [_('Full'), True])
        self._table_full_width_punct_mode_combobox.set_model(
            self._table_full_width_punct_mode_store)
        renderer_text = Gtk.CellRendererText()
        self._table_full_width_punct_mode_combobox.pack_start(
            renderer_text, True)
        self._table_full_width_punct_mode_combobox.add_attribute(
            renderer_text, "text", 0)
        for index, item in enumerate(
                self._table_full_width_punct_mode_store):
            if self._settings_dict['tabdeffullwidthpunct']['user'] == item[1]:
                self._table_full_width_punct_mode_combobox.set_active(
                    index)
        self._table_full_width_punct_mode_combobox.connect(
            "changed",
            self._on_table_full_width_punct_mode_combobox_changed)
        if self.__is_cjk:
            _options_grid_row += 1
            self._options_grid.attach(
                self._table_full_width_punct_mode_label,
                0, _options_grid_row, 1, 1)
            self._options_grid.attach(
                self._table_full_width_punct_mode_combobox,
                1, _options_grid_row, 1, 1)

        self._direct_full_width_letter_mode_label = Gtk.Label()
        self._direct_full_width_letter_mode_label.set_text(
            # Translators: A combobox to choose the letter width
            # while in “Direct input” mode.
            _('Direct input letter width:'))
        self._direct_full_width_letter_mode_label.set_tooltip_text(
            # Translators: A tooltip for the label of the combobox to
            # choose the letter width while in “Direct input” mode.
            _('Whether to use fullwidth or halfwidth\n'
              'letters in direct input mode.'))
        self._direct_full_width_letter_mode_label.set_xalign(0)
        self._direct_full_width_letter_mode_combobox = Gtk.ComboBox()
        self._direct_full_width_letter_mode_store = Gtk.ListStore(str, bool)
        self._direct_full_width_letter_mode_store.append(
            # Translators: This is the mode to use half width letters
            # while in “Direct input” mode.
            [_('Half'), False])
        self._direct_full_width_letter_mode_store.append(
            # Translators: This is the mode to use full width letters
            # while in “Direct input” mode.
            [_('Full'), True])
        self._direct_full_width_letter_mode_combobox.set_model(
            self._direct_full_width_letter_mode_store)
        renderer_text = Gtk.CellRendererText()
        self._direct_full_width_letter_mode_combobox.pack_start(
            renderer_text, True)
        self._direct_full_width_letter_mode_combobox.add_attribute(
            renderer_text, "text", 0)
        for index, item in enumerate(
                self._direct_full_width_letter_mode_store):
            if self._settings_dict['endeffullwidthletter']['user'] == item[1]:
                self._direct_full_width_letter_mode_combobox.set_active(index)
        self._direct_full_width_letter_mode_combobox.connect(
            "changed",
            self._on_direct_full_width_letter_mode_combobox_changed)
        if self.__is_cjk:
            _options_grid_row += 1
            self._options_grid.attach(
                self._direct_full_width_letter_mode_label,
                0, _options_grid_row, 1, 1)
            self._options_grid.attach(
                self._direct_full_width_letter_mode_combobox,
                1, _options_grid_row, 1, 1)

        self._direct_full_width_punct_mode_label = Gtk.Label()
        self._direct_full_width_punct_mode_label.set_text(
            # Translators: A combobox to choose the punctuation width
            # while in “Direct input” mode.
            _('Direct input punctuation width:'))
        self._direct_full_width_punct_mode_label.set_tooltip_text(
            # Translators: A tooltip for the label of the combobox to
            # choose the punctuation width while in “Direct input” mode.
            _('Whether to use fullwidth or halfwidth\n'
              'punctuation in direct input mode.'))
        self._direct_full_width_punct_mode_label.set_xalign(0)
        self._direct_full_width_punct_mode_combobox = Gtk.ComboBox()
        self._direct_full_width_punct_mode_store = Gtk.ListStore(
            str, bool)
        self._direct_full_width_punct_mode_store.append(
            # Translators: This is the mode to use half width punctuation
            # while in “Direct input” mode.
            [_('Half'), False])
        self._direct_full_width_punct_mode_store.append(
            # Translators: This is the mode to use full width punctuation
            # while in “Direct input” mode.
            [_('Full'), True])
        self._direct_full_width_punct_mode_combobox.set_model(
            self._direct_full_width_punct_mode_store)
        renderer_text = Gtk.CellRendererText()
        self._direct_full_width_punct_mode_combobox.pack_start(
            renderer_text, True)
        self._direct_full_width_punct_mode_combobox.add_attribute(
            renderer_text, "text", 0)
        for index, item in enumerate(
                self._direct_full_width_punct_mode_store):
            if self._settings_dict['endeffullwidthpunct']['user'] == item[1]:
                self._direct_full_width_punct_mode_combobox.set_active(
                    index)
        self._direct_full_width_punct_mode_combobox.connect(
            "changed",
            self._on_direct_full_width_punct_mode_combobox_changed)
        if self.__is_cjk:
            _options_grid_row += 1
            self._options_grid.attach(
                self._direct_full_width_punct_mode_label,
                0, _options_grid_row, 1, 1)
            self._options_grid.attach(
                self._direct_full_width_punct_mode_combobox,
                1, _options_grid_row, 1, 1)

        self._candidate_list_section_heading_label = Gtk.Label()
        self._candidate_list_section_heading_label.set_text(
            '<b>' + _('Candidate list') + '</b>')
        self._candidate_list_section_heading_label.set_use_markup(True)
        self._candidate_list_section_heading_label.set_xalign(0)
        _options_grid_row += 1
        self._options_grid.attach(
            self._candidate_list_section_heading_label,
            0, _options_grid_row, 2, 1)

        self._always_show_lookup_checkbutton = Gtk.CheckButton(
            # Translators: A combobox to choose whether
            # a candidate list should be shown or hidden.
            # For Chinese input methods one usually wants the
            # candidate list to be shown. But for some non-Chinese
            # input methods like the Russian “translit”, hiding
            # the candidate lists is better.
            label=_('Show candidate list'))
        self._always_show_lookup_checkbutton.set_tooltip_text(
            # Translit: A tooltip for the label of the combobox to
            # choose whether a candidate list should be shown or
            # hidden.
            _('Whether candidate lists should be shown or hidden.\n'
              'For Chinese input methods one usually wants the\n'
              'candidate lists to be shown. But for some non-Chinese\n'
              'input methods like the Russian “translit”, hiding the\n'
              'candidate lists is better.'))
        self._always_show_lookup_checkbutton.set_hexpand(False)
        self._always_show_lookup_checkbutton.set_vexpand(False)
        self._always_show_lookup_checkbutton.set_active(
            self._settings_dict['alwaysshowlookup']['user'])
        self._always_show_lookup_checkbutton.connect(
            "clicked", self._on_always_show_lookup_checkbutton)
        _options_grid_row += 1
        self._options_grid.attach(
            self._always_show_lookup_checkbutton, 0, _options_grid_row, 2, 1)

        self._lookup_table_orientation_label = Gtk.Label()
        self._lookup_table_orientation_label.set_text(
            # Translators: A combobox to choose whether the candidate
            # window should be drawn horizontally or vertically.
            _('Orientation:'))
        self._lookup_table_orientation_label.set_tooltip_text(
            # Translators: A tooltip for the label of the combobox to
            # choose whether the candidate window should be drawn
            # horizontally or vertically.
            _('Whether the lookup table showing the candidates\n'
              'should be vertical or horizontal.'))
        self._lookup_table_orientation_label.set_xalign(0)
        self._lookup_table_orientation_combobox = Gtk.ComboBox()
        self._lookup_table_orientation_store = Gtk.ListStore(str, int)
        self._lookup_table_orientation_store.append(
            [_('Horizontal'), int(IBus.Orientation.HORIZONTAL)])
        self._lookup_table_orientation_store.append(
            [_('Vertical'), int(IBus.Orientation.VERTICAL)])
        self._lookup_table_orientation_store.append(
            [_('System default'), int(IBus.Orientation.SYSTEM)])
        self._lookup_table_orientation_combobox.set_model(
            self._lookup_table_orientation_store)
        renderer_text = Gtk.CellRendererText()
        self._lookup_table_orientation_combobox.pack_start(
            renderer_text, True)
        self._lookup_table_orientation_combobox.add_attribute(
            renderer_text, "text", 0)
        for index, item in enumerate(self._lookup_table_orientation_store):
            if (self._settings_dict['lookuptableorientation']['user']
                == item[1]):
                self._lookup_table_orientation_combobox.set_active(index)
        self._lookup_table_orientation_combobox.connect(
            "changed",
            self._on_lookup_table_orientation_combobox_changed)
        _options_grid_row += 1
        self._options_grid.attach(
            self._lookup_table_orientation_label, 0, _options_grid_row, 1, 1)
        self._options_grid.attach(
            self._lookup_table_orientation_combobox,
            1, _options_grid_row, 1, 1)

        self._page_size_label = Gtk.Label()
        # Translators: Here one can choose how many suggestion
        # candidates to show in one page of the candidate list.
        self._page_size_label.set_text(_('Page size:'))
        self._page_size_label.set_tooltip_text(
            # Translators: A tooltip for the label of the adjustment
            # for the number of candidates to show in one page of the
            # candidate list.
            _('The maximum number of candidates in\n'
              'one page of the lookup table. You can switch\n'
              'pages in the lookup table using the page up/down\n'
              'keys or the arrow up/down keys.'))
        self._page_size_label.set_xalign(0)
        self._page_size_adjustment = Gtk.SpinButton()
        self._page_size_adjustment.set_visible(True)
        self._page_size_adjustment.set_can_focus(True)
        self._page_size_adjustment.set_increments(1.0, 1.0)
        self._page_size_adjustment.set_range(1.0, 10.0)
        self._page_size_adjustment.set_value(
            self._settings_dict['lookuptablepagesize']['user'])
        self._page_size_adjustment.connect(
            'value-changed', self._on_page_size_adjustment_value_changed)
        _options_grid_row += 1
        self._options_grid.attach(
            self._page_size_label, 0, _options_grid_row, 1, 1)
        self._options_grid.attach(
            self._page_size_adjustment, 1, _options_grid_row, 1, 1)

        self._keybindings_label = Gtk.Label()
        self._keybindings_label.set_text(
            '<b>' + _('Current key bindings:') + '</b>')
        self._keybindings_label.set_use_markup(True)
        self._keybindings_label.set_margin_start(margin)
        self._keybindings_label.set_margin_end(margin)
        self._keybindings_label.set_margin_top(margin)
        self._keybindings_label.set_margin_bottom(margin)
        self._keybindings_label.set_hexpand(False)
        self._keybindings_label.set_vexpand(False)
        self._keybindings_label.set_xalign(0)
        self._keybindings_treeview_scroll = Gtk.ScrolledWindow()
        self._keybindings_treeview_scroll.set_can_focus(False)
        self._keybindings_treeview_scroll.set_hexpand(False)
        self._keybindings_treeview_scroll.set_vexpand(True)
        #self._keybindings_treeview_scroll.set_shadow_type(in)
        self._keybindings_treeview = Gtk.TreeView()
        self._keybindings_treeview_model = Gtk.ListStore(str, str)
        self._keybindings_treeview.set_model(self._keybindings_treeview_model)

        user_keybindings = self._settings_dict['keybindings']['user']
        for command in sorted(user_keybindings):
            self._keybindings_treeview_model.append(
                (command, repr(user_keybindings[command])))
        keybindings_treeview_column_0 = Gtk.TreeViewColumn(
            # Translators: Column heading of the table listing the
            # existing key bindings
            _('Command'),
            Gtk.CellRendererText(),
            text=0)
        keybindings_treeview_column_0.set_sort_column_id(0)
        self._keybindings_treeview.append_column(keybindings_treeview_column_0)
        keybindings_treeview_column_1 = Gtk.TreeViewColumn(
            # Translators: Column heading of the table listing the
            # existing key bindings
            _('Key bindings'),
            Gtk.CellRendererText(),
            text=1)
        keybindings_treeview_column_1.set_sort_column_id(1)
        self._keybindings_treeview.append_column(keybindings_treeview_column_1)
        self._keybindings_treeview.get_selection().connect(
            'changed', self._on_keybindings_treeview_row_selected)
        self._keybindings_treeview.connect(
            'row-activated', self._on_keybindings_treeview_row_activated)
        self._keybindings_treeview_scroll.add(self._keybindings_treeview)
        self._keybindings_vbox.pack_start(
            self._keybindings_label, False, False, 0)
        self._keybindings_vbox.pack_start(
            self._keybindings_treeview_scroll, True, True, 0)
        self._keybindings_action_area = Gtk.Box()
        self._keybindings_action_area.set_orientation(
            Gtk.Orientation.HORIZONTAL)
        self._keybindings_action_area.set_can_focus(False)
        self._keybindings_vbox.add(
            self._keybindings_action_area)
        self._keybindings_edit_button = Gtk.Button()
        self._keybindings_edit_button_label = Gtk.Label()
        self._keybindings_edit_button_label.set_text(
            _('Edit'))
        self._keybindings_edit_button.add(
            self._keybindings_edit_button_label)
        self._keybindings_edit_button.set_tooltip_text(
            # Translators: A tooltip for the button to edit
            # the keybindings for the selected command.
            _('Edit the key bindings for the selected command'))
        self._keybindings_edit_button.set_sensitive(False)
        self._keybindings_edit_button.connect(
            'clicked', self._on_keybindings_edit_button_clicked)
        self._keybindings_default_button = Gtk.Button()
        self._keybindings_default_button_label = Gtk.Label()
        self._keybindings_default_button_label.set_text(
            _('Set to default'))
        self._keybindings_default_button.add(
            self._keybindings_default_button_label)
        self._keybindings_default_button.set_tooltip_text(
            # Translators: A tooltip for the button to set
            # the default key bindings for the selected command.
            _('Set default key bindings for the selected command'))
        self._keybindings_default_button.set_sensitive(False)
        self._keybindings_default_button.connect(
            'clicked', self._on_keybindings_default_button_clicked)
        self._keybindings_all_default_button = Gtk.Button()
        self._keybindings_all_default_button_label = Gtk.Label()
        self._keybindings_all_default_button_label.set_text(
            _('Set all to default'))
        self._keybindings_all_default_button.add(
            self._keybindings_all_default_button_label)
        self._keybindings_all_default_button.set_tooltip_text(
            # Translators: A tooltip for the button to set the
            # key bindings to default for all commands.
            _('Set default key bindings for all commands'))
        self._keybindings_all_default_button.set_sensitive(True)
        self._keybindings_all_default_button.connect(
            'clicked', self._on_keybindings_all_default_button_clicked)
        self._keybindings_action_area.add(self._keybindings_edit_button)
        self._keybindings_action_area.add(self._keybindings_default_button)
        self._keybindings_action_area.add(self._keybindings_all_default_button)
        self._keybindings_selected_command = ''
        self._keybindings_edit_popover_selected_keybinding = ''
        self._keybindings_edit_popover_selected_keybinding_index = -1
        self._keybindings_edit_popover_listbox = None
        self._keybindings_edit_popover = None
        self._keybindings_edit_popover_scroll = None
        self._keybindings_edit_popover_add_button = None
        self._keybindings_edit_popover_remove_button = None
        self._keybindings_edit_popover_default_button = None
        self._keybindings_edit_popover_up_button = None
        self._keybindings_edit_popover_down_button = None

        _options_details_grid_row = -1

        self._dynamic_adjust_checkbutton = Gtk.CheckButton(
            # Translators: A checkbox where one can choose whether the
            # order of the candidates is dynamically adjusted according
            # to how often the candidates are used.
            label=_('Dynamic adjust'))
        self._dynamic_adjust_checkbutton.set_tooltip_text(
            _('Here you can choose whether the order of the candidates is '
              + 'dynamically adjusted according to how often the candidates '
              + 'are used.'))
        self._dynamic_adjust_checkbutton.set_hexpand(False)
        self._dynamic_adjust_checkbutton.set_vexpand(False)
        self._dynamic_adjust_checkbutton.set_active(
            self._settings_dict['dynamicadjust']['user'])
        self._dynamic_adjust_checkbutton.connect(
            'clicked', self._on_dynamic_adjust_checkbutton)
        self._dynamic_adjust_forget_button = Gtk.Button()
        self._dynamic_adjust_forget_button_box = Gtk.HBox()
        self._dynamic_adjust_forget_button_label = Gtk.Label()
        self._dynamic_adjust_forget_button_label.set_text(
            _('Delete all learned data'))
        self._dynamic_adjust_forget_button_label.set_use_markup(True)
        self._dynamic_adjust_forget_button_label.set_max_width_chars(
            40)
        self._dynamic_adjust_forget_button_label.set_line_wrap(False)
        self._dynamic_adjust_forget_button_label.set_ellipsize(
            Pango.EllipsizeMode.START)
        self._dynamic_adjust_forget_button_box.pack_start(
            self._dynamic_adjust_forget_button_label, False, False, 0)
        self._dynamic_adjust_forget_button.add(
            self._dynamic_adjust_forget_button_box)
        self._dynamic_adjust_forget_button.connect(
            'clicked', self._on_dynamic_adjust_forget_button)
        _options_details_grid_row += 1
        self._options_details_grid.attach(
            self._dynamic_adjust_checkbutton,
            0, _options_details_grid_row, 1, 1)
        self._options_details_grid.attach(
            self._dynamic_adjust_forget_button,
            1, _options_details_grid_row, 1, 1)

        self._onechar_mode_label = Gtk.Label()
        self._onechar_mode_label.set_text(
            # Translators: A combobox to choose whether only single
            # character candidates should be shown.
            _('Compose:'))
        self._onechar_mode_label.set_tooltip_text(
            # Translators: A tooltip for label of the combobox to
            # choose whether only single character candidates should
            # be shown.
            _('If this is set to “single char”, only single\n'
              'character candidates will be shown. If it is\n'
              'set to “Phrase” candidates consisting of\n'
              'several characters may be shown.'))
        self._onechar_mode_label.set_xalign(0)
        self._onechar_mode_combobox = Gtk.ComboBox()
        self._onechar_mode_store = Gtk.ListStore(str, int)
        self._onechar_mode_store.append(
            [_('Phrase'), False])
        self._onechar_mode_store.append(
            [_('Single Char'), True])
        self._onechar_mode_combobox.set_model(
            self._onechar_mode_store)
        renderer_text = Gtk.CellRendererText()
        self._onechar_mode_combobox.pack_start(
            renderer_text, True)
        self._onechar_mode_combobox.add_attribute(
            renderer_text, "text", 0)
        for index, item in enumerate(self._onechar_mode_store):
            if self._settings_dict['onechar']['user'] == item[1]:
                self._onechar_mode_combobox.set_active(index)
        self._onechar_mode_combobox.connect(
            "changed", self._on_onechar_mode_combobox_changed)
        if self.__is_cjk:
            _options_details_grid_row += 1
            self._options_details_grid.attach(
                self._onechar_mode_label,
                0, _options_details_grid_row, 1, 1)
            self._options_details_grid.attach(
                self._onechar_mode_combobox,
                1, _options_details_grid_row, 1, 1)

        self._autoselect_mode_checkbutton = Gtk.CheckButton(
            # Translators: A combobox to choose whether the first
            # candidate will be automatically selected during typing.
            label=_('Auto select'))
        self._autoselect_mode_checkbutton.set_tooltip_text(
            # Translators: A tooltip for the label of the combobox to
            # choose whether the first candidate will be automatically
            # select during typing.
            _('If set to “Yes”, this does the following 4 things:\n'
              '1) When typing “Return”, commit the \n'
              '   candidate + line-feed\n'
              '2) When typing Tab, commit the candidate\n'
              '3) When committing using a commit key, commit\n'
              '   the candidate + " "\n'
              '4) If typing the next character matches no candidates,\n'
              '   commit the first candidate of the previous match.\n'
              '   (Mostly needed for non-Chinese input methods like\n'
              '   the Russian “translit”)'))
        self._autoselect_mode_checkbutton.set_hexpand(False)
        self._autoselect_mode_checkbutton.set_vexpand(False)
        self._autoselect_mode_checkbutton.set_active(
            self._settings_dict['autoselect']['user'])
        self._autoselect_mode_checkbutton.connect(
            'clicked', self._on_autoselect_mode_checkbutton)
        _options_details_grid_row += 1
        self._options_details_grid.attach(
            self._autoselect_mode_checkbutton,
            0, _options_details_grid_row, 2, 1)

        self._autocommit_mode_label = Gtk.Label()
        self._autocommit_mode_label.set_text(
            # Translators: A combobox to choose whether automatic
            # commits go into the preëdit or into the application
            _('Autocommit mode:'))
        self._autocommit_mode_label.set_tooltip_text(
            # Translators: A tooltip for the label of the combobox to
            # choose whether automatic commits go into the preëdit or
            # into the application.
            _('Committing with the commit keys or with the mouse\n'
              'always commits to the application. This option is about\n'
              '“automatic” commits which may happen when\n'
              'one just continues typing input without committing\n'
              'manually. From time to time, “automatic” commits will\n'
              'happen then.\n'
              '“Direct” means such “automatic” commits go directly\n'
              'into the application, “Normal” means they get committed\n'
              'to preedit.'))
        self._autocommit_mode_label.set_xalign(0)
        self._autocommit_mode_combobox = Gtk.ComboBox()
        self._autocommit_mode_store = Gtk.ListStore(str, int)
        self._autocommit_mode_store.append(
            [_('Normal'), False])
        self._autocommit_mode_store.append(
            [_('Direct'), True])
        self._autocommit_mode_combobox.set_model(
            self._autocommit_mode_store)
        renderer_text = Gtk.CellRendererText()
        self._autocommit_mode_combobox.pack_start(
            renderer_text, True)
        self._autocommit_mode_combobox.add_attribute(
            renderer_text, "text", 0)
        for index, item in enumerate(self._autocommit_mode_store):
            if self._settings_dict['autocommit']['user'] == item[1]:
                self._autocommit_mode_combobox.set_active(index)
        self._autocommit_mode_combobox.connect(
            "changed", self._on_autocommit_mode_combobox_changed)
        if self.__user_can_define_phrase and self.__rules:
            _options_details_grid_row += 1
            self._options_details_grid.attach(
                self._autocommit_mode_label,
                0, _options_details_grid_row, 1, 1)
            self._options_details_grid.attach(
                self._autocommit_mode_combobox,
                1, _options_details_grid_row, 1, 1)

        self._commit_invalid_mode_label = Gtk.Label()
        self._commit_invalid_mode_label.set_text(
            # Translators: A combobox to choose whether only single
            # character candidates should be shown.
            _('Action when typing invalid character:'))
        self._commit_invalid_mode_label.set_tooltip_text(
            # Translators: A tooltip for label of the combobox to
            # choose whether only single character candidates should
            # be shown.
            _('Determines what happens when a character which is not '
              'in the set of valid input characters for this table '
              'is typed: With “commit current candidate”, the currently '
              'selected candidate is inserted. With “commit typed keys”, '
              'the raw characters typed so far during the candidate '
              'selection process will be inserted instead. In all cases, '
              'the candidate selection ends when an invalid character is '
              'typed and the character in question is inserted immediately '
              'after the text that results from the options listed above.'))
        self._commit_invalid_mode_label.set_xalign(0)
        self._commit_invalid_mode_combobox = Gtk.ComboBox()
        self._commit_invalid_mode_store = Gtk.ListStore(str, int)
        self._commit_invalid_mode_store.append(
            [_('Commit current candidate'), 0])
        self._commit_invalid_mode_store.append(
            [_('Commit typed keys'), 1])
        self._commit_invalid_mode_combobox.set_model(
            self._commit_invalid_mode_store)
        renderer_text = Gtk.CellRendererText()
        self._commit_invalid_mode_combobox.pack_start(
            renderer_text, True)
        self._commit_invalid_mode_combobox.add_attribute(
            renderer_text, "text", 0)
        for index, item in enumerate(self._commit_invalid_mode_store):
            if self._settings_dict['commitinvalidmode']['user'] == item[1]:
                self._commit_invalid_mode_combobox.set_active(index)
        self._commit_invalid_mode_combobox.connect(
            "changed", self._on_commit_invalid_mode_combobox_changed)
        _options_details_grid_row += 1
        self._options_details_grid.attach(
            self._commit_invalid_mode_label,
            0, _options_details_grid_row, 1, 1)
        self._options_details_grid.attach(
            self._commit_invalid_mode_combobox,
            1, _options_details_grid_row, 1, 1)

        self._autowildcard_mode_checkbutton = Gtk.CheckButton(
            # Translators: A combobox to choose whether a wildcard
            # should be automatically appended to the input.
            label=_('Auto wildcard'))
        self._autowildcard_mode_checkbutton.set_tooltip_text(
            # Translators: A tooltip for the label of the combobox to
            # choose whether a wildcard should be automatically
            # appended to the input.
            _('If yes, a multi wildcard will be automatically\n'
              'appended to the end of the input string.'))
        self._autowildcard_mode_checkbutton.set_hexpand(False)
        self._autowildcard_mode_checkbutton.set_vexpand(False)
        self._autowildcard_mode_checkbutton.set_active(
            self._settings_dict['autowildcard']['user'])
        self._autowildcard_mode_checkbutton.connect(
            'clicked', self._on_autowildcard_mode_checkbutton)
        _options_details_grid_row += 1
        self._options_details_grid.attach(
            self._autowildcard_mode_checkbutton,
            0, _options_details_grid_row, 2, 1)

        self._single_wildcard_char_label = Gtk.Label()
        self._single_wildcard_char_label.set_text(
            # Translators: This single character is a placeholder
            # to match a any single character
            _('Single wildcard character:'))
        self._single_wildcard_char_label.set_tooltip_text(
            # Translators: This is a tooltip for the label of the
            # entry where one can choose the wildcard to match a
            # single character.
            _('The wildcard to match any single character.\n'
              'Type RETURN or ENTER to confirm after changing the wildcard.'))
        self._single_wildcard_char_label.set_xalign(0)
        self._single_wildcard_char_entry = Gtk.Entry()
        self._single_wildcard_char_entry.set_max_length(1)
        self._single_wildcard_char_entry.set_text(
            self._settings_dict['singlewildcardchar']['user'])
        self._single_wildcard_char_entry.connect(
            'notify::text', self._on_single_wildcard_char_entry)
        _options_details_grid_row += 1
        self._options_details_grid.attach(
            self._single_wildcard_char_label,
            0, _options_details_grid_row, 1, 1)
        self._options_details_grid.attach(
            self._single_wildcard_char_entry,
            1, _options_details_grid_row, 1, 1)

        self._multi_wildcard_char_label = Gtk.Label()
        self._multi_wildcard_char_label.set_text(
            # Translators: This single character is a placeholder
            # to match a any number of characters
            _('Multi wildcard character:'))
        self._multi_wildcard_char_label.set_tooltip_text(
            # Translators: This is a tooltip for the label of the
            # entry where one can choose the wildcard to match any
            # number of candidates.
            _('The wildcard used to match any number of characters.\n'
              'Type RETURN or ENTER to confirm after changing the wildcard.'))
        self._multi_wildcard_char_label.set_xalign(0)
        self._multi_wildcard_char_entry = Gtk.Entry()
        self._multi_wildcard_char_entry.set_max_length(1)
        self._multi_wildcard_char_entry.set_text(
            self._settings_dict['multiwildcardchar']['user'])
        self._multi_wildcard_char_entry.connect(
            'notify::text', self._on_multi_wildcard_char_entry)
        _options_details_grid_row += 1
        self._options_details_grid.attach(
            self._multi_wildcard_char_label,
            0, _options_details_grid_row, 1, 1)
        self._options_details_grid.attach(
            self._multi_wildcard_char_entry,
            1, _options_details_grid_row, 1, 1)

        self._use_dark_theme_checkbutton = Gtk.CheckButton(
            # Translators: A combobox to choose whether
            # the color scheme for a dark theme should be used.
            label=_('Use dark theme'))
        self._use_dark_theme_checkbutton.set_tooltip_text(
            # Translators: A tooltip for the label of the combobox to
            # choose whether the color scheme for a dark theme should
            # be used.
            _('If yes, the color scheme for a dark theme will be used.'))
        self._use_dark_theme_checkbutton.set_hexpand(False)
        self._use_dark_theme_checkbutton.set_vexpand(False)
        self._use_dark_theme_checkbutton.set_active(
            self._settings_dict['darktheme']['user'])
        self._use_dark_theme_checkbutton.connect(
            'clicked', self._on_use_dark_theme_checkbutton)
        _options_details_grid_row += 1
        self._options_details_grid.attach(
            self._use_dark_theme_checkbutton,
            0, _options_details_grid_row, 2, 1)

        self._error_sound_checkbutton = Gtk.CheckButton(
            # Translators: A checkbox where one can choose whether a
            # sound is played on error
            label=_('Play sound file on error'))
        self._error_sound_checkbutton.set_tooltip_text(
            _('Here you can choose whether a sound file is played '
              + 'if an error occurs. '
              + 'If the simpleaudio module for Python3 is not installed, '
              + 'this option does nothing.'))
        self._error_sound_checkbutton.set_hexpand(False)
        self._error_sound_checkbutton.set_vexpand(False)
        self._error_sound_checkbutton.set_active(
            self._settings_dict['errorsound']['user'])
        self._error_sound_checkbutton.connect(
            'clicked', self._on_error_sound_checkbutton)
        self._error_sound_file_button = Gtk.Button()
        self._error_sound_file_button_box = Gtk.HBox()
        self._error_sound_file_button_label = Gtk.Label()
        self._error_sound_file_button_label.set_text(
            self._settings_dict['errorsoundfile']['user'])
        self._error_sound_file_button_label.set_use_markup(True)
        self._error_sound_file_button_label.set_max_width_chars(
            40)
        self._error_sound_file_button_label.set_line_wrap(False)
        self._error_sound_file_button_label.set_ellipsize(
            Pango.EllipsizeMode.START)
        self._error_sound_file_button_box.pack_start(
            self._error_sound_file_button_label, False, False, 0)
        self._error_sound_file_button.add(
            self._error_sound_file_button_box)
        self._error_sound_file_button.connect(
            'clicked', self._on_error_sound_file_button)
        _options_details_grid_row += 1
        self._options_details_grid.attach(
            self._error_sound_checkbutton, 0, _options_details_grid_row, 1, 1)
        self._options_details_grid.attach(
            self._error_sound_file_button, 1, _options_details_grid_row, 1, 1)
        self._error_sound_object = it_sound.SoundObject(
            os.path.expanduser(self._settings_dict['errorsoundfile']['user']),
            audio_backend=self._settings_dict['soundbackend']['user'])

        self._debug_level_label = Gtk.Label()
        self._debug_level_label.set_text(
            # Translators: When the debug level is greater than 0,
            # debug information may be printed to the log file and
            # debug information may also be shown graphically.
            _('Debug level:'))
        self._debug_level_label.set_tooltip_text(
            # Translators: This is a tooltip for the label for the
            # adjustment of the debug level.
            _('When greater than 0, debug information may be '
              'printed to the log file and debug information '
              'may also be shown graphically.'))
        self._debug_level_label.set_xalign(0)
        self._debug_level_adjustment = Gtk.SpinButton()
        self._debug_level_adjustment.set_visible(True)
        self._debug_level_adjustment.set_can_focus(True)
        self._debug_level_adjustment.set_increments(1.0, 1.0)
        self._debug_level_adjustment.set_range(0.0, 255.0)
        self._debug_level_adjustment.set_value(
            self._settings_dict['debuglevel']['user'])
        self._debug_level_adjustment.connect(
            'value-changed',
            self._on_debug_level_adjustment_value_changed)
        _options_details_grid_row += 1
        self._options_details_grid.attach(
            self._debug_level_label, 0, _options_details_grid_row, 1, 1)
        self._options_details_grid.attach(
            self._debug_level_adjustment, 1, _options_details_grid_row, 1, 1)

        # name, label, check button
        self._input_method_menu_tuple: Tuple[
            List[Union[str, Optional[Gtk.CheckButton]]], ...] = (
            (["chinese_mode", _("Chinese mode"), None],
             ["letter_width", _("Letter width"), None],
             ["punctuation_width", _("Punctuation width"), None],
             ["pinyin_mode", _("Pinyin mode"), None],
             ["suggestion_mode", _("Suggestion mode"), None],
             ["onechar_mode", _("Onechar mode"), None],
             ["autocommit_mode", _("Autocommit mode"), None]))

        _input_method_menu_grid_row = -1

        for item in self._input_method_menu_tuple:
            name, label, button = item
            _input_method_menu_grid_row += 1
            button = Gtk.CheckButton(label=label)
            button.set_hexpand(False)
            button.set_vexpand(False)
            if name in self._settings_dict['inputmethodmenu']['user']:
                button.set_active(True)
            else:
                button.set_active(False)
            button.connect(
                'clicked', self._on_input_method_menu_checkbutton)
            self._input_method_menu_grid.attach(
                button, 0, _input_method_menu_grid_row, 1, 1)
            item[2] = button

        self.show_all() # pylint: disable=no-member

        self._notebook.set_current_page(0) # Has to be after show_all()

        self._gsettings.connect('changed', self._on_gsettings_value_changed)

    def _fill_settings_dict(self) -> None:
        '''Fill a dictionary with the default and user settings for all
        settings keys.

        The default settings start with the defaults from the
        gsettings schema. Some of these generic default values may be
        overridden by more specific default settings coming from the
        specific database of this table input method. After this
        possible modification from the database we have the final default
        settings for this specific table input method.

        The user settings start with a copy of these final default settings,
        then they are possibly modified by user gsettings.

        Keeping a copy of the default settings in the settings dictionary
        makes it easy to revert some or all settings to the defaults.
        '''
        self._settings_dict = {}

        default_single_wildcard_char = it_util.variant_to_value(
            self._gsettings.get_default_value('singlewildcardchar'))
        if self.tabsqlitedb.ime_properties.get('single_wildcard_char'):
            default_single_wildcard_char = self.tabsqlitedb.ime_properties.get(
                'single_wildcard_char')
        user_single_wildcard_char = it_util.variant_to_value(
            self._gsettings.get_user_value('singlewildcardchar'))
        if user_single_wildcard_char is None:
            user_single_wildcard_char = default_single_wildcard_char

        self._settings_dict['singlewildcardchar'] = {
            'default': default_single_wildcard_char,
            'user': user_single_wildcard_char,
            'set_function': self.set_single_wildcard_char}

        default_multi_wildcard_char = it_util.variant_to_value(
            self._gsettings.get_default_value('multiwildcardchar'))
        if self.tabsqlitedb.ime_properties.get('multi_wildcard_char'):
            default_multi_wildcard_char = self.tabsqlitedb.ime_properties.get(
                'multi_wildcard_char')
        user_multi_wildcard_char = it_util.variant_to_value(
            self._gsettings.get_user_value('multiwildcardchar'))
        if user_multi_wildcard_char is None:
            user_multi_wildcard_char = default_multi_wildcard_char

        self._settings_dict['multiwildcardchar'] = {
            'default': default_multi_wildcard_char,
            'user': user_multi_wildcard_char,
            'set_function': self.set_multi_wildcard_char}

        default_keybindings = it_util.get_default_keybindings(
            self._gsettings, self.tabsqlitedb)
        # copy the updated default keybindings, i.e. the default
        # keybindings for this table, into the user keybindings:
        user_keybindings = copy.deepcopy(default_keybindings)
        user_keybindings_gsettings = it_util.variant_to_value(
            self._gsettings.get_user_value('keybindings'))
        if not user_keybindings_gsettings:
            user_keybindings_gsettings = {}
        it_util.dict_update_existing_keys(
            user_keybindings, user_keybindings_gsettings)

        self._settings_dict['keybindings'] = {
            'default': default_keybindings,
            'user': user_keybindings,
            'set_function': self.set_keybindings}

        default_always_show_lookup = it_util.variant_to_value(
            self._gsettings.get_default_value('alwaysshowlookup'))
        if self.tabsqlitedb.ime_properties.get('always_show_lookup'):
            default_always_show_lookup = (
                self.tabsqlitedb.ime_properties.get(
                    'always_show_lookup').lower() == 'true')
        user_always_show_lookup = it_util.variant_to_value(
            self._gsettings.get_user_value('alwaysshowlookup'))
        if user_always_show_lookup is None:
            user_always_show_lookup = default_always_show_lookup

        self._settings_dict['alwaysshowlookup'] = {
            'default': default_always_show_lookup,
            'user': user_always_show_lookup,
            'set_function': self.set_always_show_lookup}

        default_page_size = it_util.variant_to_value(
            self._gsettings.get_default_value('lookuptablepagesize'))
        for index in range(1, 10):
            if not default_keybindings[f'commit_candidate_{index + 1}']:
                default_page_size = min(index, default_page_size)
                break
        user_page_size = it_util.variant_to_value(
            self._gsettings.get_user_value('lookuptablepagesize'))
        if user_page_size is None:
            user_page_size = default_page_size

        self._settings_dict['lookuptablepagesize'] = {
            'default': int(default_page_size),
            'user': int(user_page_size),
            'set_function': self.set_page_size}

        default_lookup_table_orientation = it_util.variant_to_value(
            self._gsettings.get_default_value('lookuptableorientation'))
        default_lookup_table_orientation = self.tabsqlitedb.get_orientation()
        user_lookup_table_orientation = it_util.variant_to_value(
            self._gsettings.get_user_value('lookuptableorientation'))
        if user_lookup_table_orientation is None:
            user_lookup_table_orientation = default_lookup_table_orientation

        self._settings_dict['lookuptableorientation'] = {
            'default': default_lookup_table_orientation,
            'user': user_lookup_table_orientation,
            'set_function': self.set_lookup_table_orientation}

        default_chinese_mode = it_util.variant_to_value(
            self._gsettings.get_default_value('chinesemode'))
        default_chinese_mode = it_util.get_default_chinese_mode(
            self.tabsqlitedb)
        user_chinese_mode = it_util.variant_to_value(
            self._gsettings.get_user_value('chinesemode'))
        if user_chinese_mode is None:
            user_chinese_mode = default_chinese_mode

        self._settings_dict['chinesemode'] = {
            'default': default_chinese_mode,
            'user': user_chinese_mode,
            'set_function': self.set_chinese_mode}

        default_input_mode = it_util.variant_to_value(
            self._gsettings.get_default_value('inputmode'))
        user_input_mode = it_util.variant_to_value(
            self._gsettings.get_value('inputmode'))

        self._settings_dict['inputmode'] = {
            'default': default_input_mode,
            'user': user_input_mode,
            'set_function': self.set_input_mode}

        default_remember_input_mode = it_util.variant_to_value(
            self._gsettings.get_default_value('rememberinputmode'))
        user_remember_input_mode = it_util.variant_to_value(
            self._gsettings.get_value('rememberinputmode'))

        self._settings_dict['rememberinputmode'] = {
            'default': default_remember_input_mode,
            'user': user_remember_input_mode,
            'set_function': self.set_remember_input_mode}

        default_dark_theme = it_util.variant_to_value(
            self._gsettings.get_default_value('darktheme'))
        user_dark_theme = it_util.variant_to_value(
            self._gsettings.get_value('darktheme'))

        self._settings_dict['darktheme'] = {
            'default': default_dark_theme,
            'user': user_dark_theme,
            'set_function': self.set_dark_theme}

        default_dynamic_adjust = it_util.variant_to_value(
            self._gsettings.get_default_value('dynamicadjust'))
        if self.tabsqlitedb.ime_properties.get('dynamic_adjust'):
            default_dynamic_adjust = (
                self.tabsqlitedb.ime_properties.get(
                    'dynamic_adjust').lower() == 'true')
        user_dynamic_adjust = it_util.variant_to_value(
            self._gsettings.get_user_value('dynamicadjust'))
        if user_dynamic_adjust is None:
            user_dynamic_adjust = default_dynamic_adjust

        self._settings_dict['dynamicadjust'] = {
            'default': default_dynamic_adjust,
            'user': user_dynamic_adjust,
            'set_function': self.set_dynamic_adjust}

        default_error_sound = it_util.variant_to_value(
            self._gsettings.get_default_value('errorsound'))
        user_error_sound = it_util.variant_to_value(
            self._gsettings.get_value('errorsound'))

        self._settings_dict['errorsound'] = {
            'default': default_error_sound,
            'user': user_error_sound,
            'set_function': self.set_error_sound}

        default_error_sound_file = it_util.variant_to_value(
            self._gsettings.get_default_value('errorsoundfile'))
        user_error_sound_file = it_util.variant_to_value(
            self._gsettings.get_value('errorsoundfile'))

        self._settings_dict['errorsoundfile'] = {
            'default': default_error_sound_file,
            'user': user_error_sound_file,
            'set_function': self.set_error_sound_file}

        default_sound_backend = it_util.variant_to_value(
            self._gsettings.get_default_value('soundbackend'))
        user_sound_backend = it_util.variant_to_value(
            self._gsettings.get_value('soundbackend'))

        self._settings_dict['soundbackend'] = {
            'default': default_sound_backend,
            'user': user_sound_backend,
            'set_function': self.set_sound_backend}

        default_debug_level = it_util.variant_to_value(
            self._gsettings.get_default_value('debuglevel'))
        user_debug_level = it_util.variant_to_value(
            self._gsettings.get_value('debuglevel'))

        self._settings_dict['debuglevel'] = {
            'default': default_debug_level,
            'user': user_debug_level,
            'set_function': self.set_debug_level}

        default_table_full_width_letter_mode = it_util.variant_to_value(
            self._gsettings.get_default_value('tabdeffullwidthletter'))
        if self.tabsqlitedb.ime_properties.get('def_full_width_letter'):
            default_table_full_width_letter_mode = (
                self.tabsqlitedb.ime_properties.get(
                    'def_full_width_letter').lower() == 'true')
        user_table_full_width_letter_mode = it_util.variant_to_value(
            self._gsettings.get_user_value('tabdeffullwidthletter'))
        if user_table_full_width_letter_mode is None:
            user_table_full_width_letter_mode = (
                default_table_full_width_letter_mode)

        self._settings_dict['tabdeffullwidthletter'] = {
            'default': default_table_full_width_letter_mode,
            'user': user_table_full_width_letter_mode,
            'set_function': self.set_table_full_width_letter_mode}

        default_table_full_width_punct_mode = (
            it_util.variant_to_value(
                self._gsettings.get_default_value('tabdeffullwidthpunct')))
        if self.tabsqlitedb.ime_properties.get('def_full_width_punct'):
            default_table_full_width_punct_mode = (
                self.tabsqlitedb.ime_properties.get(
                    'def_full_width_punct').lower() == 'true')
        user_table_full_width_punct_mode = it_util.variant_to_value(
            self._gsettings.get_user_value('tabdeffullwidthpunct'))
        if user_table_full_width_punct_mode is None:
            user_table_full_width_punct_mode = (
                default_table_full_width_punct_mode)

        self._settings_dict['tabdeffullwidthpunct'] = {
            'default': default_table_full_width_punct_mode,
            'user': user_table_full_width_punct_mode,
            'set_function': self.set_table_full_width_punct_mode}

        default_direct_full_width_letter_mode = it_util.variant_to_value(
            self._gsettings.get_default_value('endeffullwidthletter'))
        user_direct_full_width_letter_mode = it_util.variant_to_value(
            self._gsettings.get_value('endeffullwidthletter'))

        self._settings_dict['endeffullwidthletter'] = {
            'default': default_direct_full_width_letter_mode,
            'user': user_direct_full_width_letter_mode,
            'set_function': self.set_direct_full_width_letter_mode}

        default_direct_full_width_punct_mode = it_util.variant_to_value(
            self._gsettings.get_default_value('endeffullwidthpunct'))
        user_direct_full_width_punct_mode = it_util.variant_to_value(
            self._gsettings.get_value('endeffullwidthpunct'))

        self._settings_dict['endeffullwidthpunct'] = {
            'default': default_direct_full_width_punct_mode,
            'user': user_direct_full_width_punct_mode,
            'set_function': self.set_direct_full_width_punct_mode}

        default_onechar_mode = it_util.variant_to_value(
            self._gsettings.get_default_value('onechar'))
        user_onechar_mode = it_util.variant_to_value(
            self._gsettings.get_value('onechar'))

        self._settings_dict['onechar'] = {
            'default': default_onechar_mode,
            'user': user_onechar_mode,
            'set_function': self.set_onechar_mode}

        default_autoselect_mode = it_util.variant_to_value(
            self._gsettings.get_default_value('autoselect'))
        if self.tabsqlitedb.ime_properties.get('auto_select'):
            default_autoselect_mode = (
                self.tabsqlitedb.ime_properties.get(
                    'auto_select').lower() == 'true')
        user_autoselect_mode = it_util.variant_to_value(
            self._gsettings.get_user_value('autoselect'))
        if user_autoselect_mode is None:
            user_autoselect_mode = default_autoselect_mode

        self._settings_dict['autoselect'] = {
            'default': default_autoselect_mode,
            'user': user_autoselect_mode,
            'set_function': self.set_autoselect_mode}

        default_autocommit_mode = it_util.variant_to_value(
            self._gsettings.get_default_value('autocommit'))
        if self.tabsqlitedb.ime_properties.get('auto_commit'):
            default_autocommit_mode = (
                self.tabsqlitedb.ime_properties.get(
                    'auto_commit').lower() == 'true')
        user_autocommit_mode = it_util.variant_to_value(
            self._gsettings.get_user_value('autocommit'))
        if user_autocommit_mode is None:
            user_autocommit_mode = default_autocommit_mode

        self._settings_dict['autocommit'] = {
            'default': default_autocommit_mode,
            'user': user_autocommit_mode,
            'set_function': self.set_autocommit_mode}

        default_commit_invalid_mode = it_util.variant_to_value(
            self._gsettings.get_default_value('commitinvalidmode'))
        user_commit_invalid_mode = it_util.variant_to_value(
            self._gsettings.get_value('commitinvalidmode'))

        self._settings_dict['commitinvalidmode'] = {
            'default': default_commit_invalid_mode,
            'user': user_commit_invalid_mode,
            'set_function': self.set_commit_invalid_mode}

        default_autowildcard_mode = it_util.variant_to_value(
            self._gsettings.get_default_value('autowildcard'))
        if self.tabsqlitedb.ime_properties.get('auto_wildcard'):
            default_autowildcard_mode = (
                self.tabsqlitedb.ime_properties.get(
                    'auto_wildcard').lower() == 'true')
        user_autowildcard_mode = it_util.variant_to_value(
            self._gsettings.get_user_value('autowildcard'))
        if user_autowildcard_mode is None:
            user_autowildcard_mode = default_autowildcard_mode

        self._settings_dict['autowildcard'] = {
            'default': default_autowildcard_mode,
            'user': user_autowildcard_mode,
            'set_function': self.set_autowildcard_mode}

        default_input_method_menu = it_util.variant_to_value(
            self._gsettings.get_default_value('inputmethodmenu'))
        user_input_method_menu = it_util.variant_to_value(
            self._gsettings.get_value('inputmethodmenu'))
        if user_input_method_menu is None:
            user_input_method_menu = default_input_method_menu

        self._settings_dict['inputmethodmenu'] = {
            'default': default_input_method_menu,
            'user': user_input_method_menu,
            'set_function': self.set_input_method_menu}

    @staticmethod
    def run_message_dialog(
            message: str,
            message_type: Gtk.MessageType = Gtk.MessageType.INFO) -> None:
        '''Run a dialog to show an error or warning message'''
        dialog = Gtk.MessageDialog(
            flags=Gtk.DialogFlags.MODAL,
            message_type=message_type,
            buttons=Gtk.ButtonsType.OK,
            message_format=message)
        dialog.run()
        dialog.destroy()

    def _run_are_you_sure_dialog(self, message: str) -> Gtk.ResponseType:
        '''
        Run a dialog to show a “Are you sure?” message.

        Returns Gtk.ResponseType.OK or Gtk.ResponseType.CANCEL (an enum)
        '''
        confirm_question = Gtk.Dialog(
            title=_('Are you sure?'),
            parent=self)
        confirm_question.add_button(_('_Cancel'), Gtk.ResponseType.CANCEL)
        confirm_question.add_button(_('_OK'), Gtk.ResponseType.OK)
        box = confirm_question.get_content_area()
        label = Gtk.Label()
        label.set_text(
            '<span size="large" color="#ff0000"><b>'
            + html.escape(message)
            + '</b></span>')
        label.set_use_markup(True)
        label.set_max_width_chars(40)
        label.set_line_wrap(True)
        label.set_line_wrap_mode(Pango.WrapMode.WORD_CHAR)
        label.set_xalign(0)
        margin = 10
        label.set_margin_start(margin)
        label.set_margin_end(margin)
        label.set_margin_top(margin)
        label.set_margin_bottom(margin)
        box.add(label)
        confirm_question.show_all()
        response = confirm_question.run()
        confirm_question.destroy()
        while Gtk.events_pending():
            Gtk.main_iteration()
        return response

    def check_instance(self) -> bool:
        '''
        Check whether another instance of the setup tool is running already
        '''
        if (dbus.SessionBus().request_name("org.ibus.table")
                != dbus.bus.REQUEST_NAME_REPLY_PRIMARY_OWNER):
            self.__class__.run_message_dialog(
                _("Another instance of this app is already running."),
                Gtk.MessageType.ERROR)
            sys.exit(1)
        else:
            return False

    @staticmethod
    def _on_delete_event(*_args: Any) -> None:
        '''The window has been deleted, probably by the window manager.'''
        LOGGER.info('Window deleted by the window manager.')
        if GLIB_MAIN_LOOP is not None:
            GLIB_MAIN_LOOP.quit()
        else:
            raise RuntimeError("GLIB_MAIN_LOOP not initialized!")

    @staticmethod
    def _on_destroy_event(*_args: Any) -> None:
        '''The window has been destroyed.'''
        LOGGER.info('Window destroyed.')
        if GLIB_MAIN_LOOP is not None:
            GLIB_MAIN_LOOP.quit()
        else:
            raise RuntimeError("GLIB_MAIN_LOOP not initialized!")

    @staticmethod
    def _on_close_clicked(_button: Gtk.Button) -> None:
        '''The button to close the dialog has been clicked.'''
        LOGGER.info('Close button clicked.')
        if GLIB_MAIN_LOOP is not None:
            GLIB_MAIN_LOOP.quit()
        else:
            raise RuntimeError("GLIB_MAIN_LOOP not initialized!")

    def _on_gsettings_value_changed(
            self, _settings: Gio.Settings, key: str) -> None:
        '''
        Called when a value in the settings has been changed.

        :param settings: The settings object
        :type settings: Gio.Settings object
        :param key: The key of the setting which has changed
        :type key: String
        '''
        value = it_util.variant_to_value(self._gsettings.get_value(key))
        LOGGER.info('Settings changed: key=%s value=%s\n', key, value)

        if key in self._settings_dict:
            self._settings_dict[key]['set_function'](value,
                                                     update_gsettings=False)
            return
        LOGGER.error('Unknown key\n')
        return

    @staticmethod
    def _on_about_button_clicked(_button: Gtk.Button) -> None:
        '''
        The “About” button has been clicked

        :param _button: The “About” button
        '''
        it_util.ItAboutDialog()

    def _on_restore_all_defaults_button_clicked(
            self, _button: Gtk.Button) -> None:
        '''
        Restore all default settings
        '''
        self._restore_all_defaults_button.set_sensitive(False)
        response = self._run_are_you_sure_dialog(
            # Translators: This is the text in the centre of a small
            # dialog window, trying to confirm whether the user is
            # really sure to restore all default settings.
            _('Do you really want to restore all default settings?'))
        if response == Gtk.ResponseType.OK:
            LOGGER.info('Restoring all defaults.')
            for _key, value in self._settings_dict.items():
                value['set_function'](value['default'], update_gsettings=True)
                # Call it again with update_gsettings=False to make
                # sure the active state of checkbuttons etc.  is
                # updated immediately:
                value['set_function'](value['default'], update_gsettings=False)
        else:
            LOGGER.info('Restore all defaults cancelled.')
        self._restore_all_defaults_button.set_sensitive(True)

    def _on_single_wildcard_char_entry(
            self, widget: Gtk.Entry, _property_spec: Any) -> None:
        '''
        The character to be used as a single wildcard has been changed.
        '''
        self.set_single_wildcard_char(
            widget.get_text(), update_gsettings=True)

    def _on_multi_wildcard_char_entry(
            self, widget: Gtk.Entry, _property_spec: Any) -> None:
        '''
        The character to be used as a multi wildcard has been changed.
        '''
        self.set_multi_wildcard_char(
            widget.get_text(), update_gsettings=True)

    def _on_page_size_adjustment_value_changed(
            self, _widget: Gtk.SpinButton) -> None:
        '''
        The page size of the lookup table has been changed.
        '''
        self.set_page_size(
            self._page_size_adjustment.get_value(), update_gsettings=True)

    def _on_lookup_table_orientation_combobox_changed(
            self, widget: Gtk.ComboBox) -> None:
        '''
        A change of the lookup table orientation has been requested
        with the combobox
        '''
        tree_iter = widget.get_active_iter()
        if tree_iter is not None:
            model = widget.get_model()
            orientation = model[tree_iter][1]
            self.set_lookup_table_orientation(
                orientation, update_gsettings=True)

    def _on_remember_input_mode_combobox_changed(
            self, widget: Gtk.ComboBox) -> None:
        '''
        A change of the remember input mode has been requested
        with the combobox
        '''
        tree_iter = widget.get_active_iter()
        if tree_iter is not None:
            model = widget.get_model()
            remember_input_mode = model[tree_iter][1]
            self.set_remember_input_mode(
                remember_input_mode, update_gsettings=True)

    def _on_chinese_mode_combobox_changed(self, widget: Gtk.ComboBox) -> None:
        '''
        A change of the Chinese mode has been requested
        with the combobox
        '''
        tree_iter = widget.get_active_iter()
        if tree_iter is not None:
            model = widget.get_model()
            chinese_mode = model[tree_iter][1]
            self.set_chinese_mode(
                chinese_mode, update_gsettings=True)

    def _on_onechar_mode_combobox_changed(self, widget: Gtk.ComboBox) -> None:
        '''
        A change of the onechar mode has been requested
        with the combobox
        '''
        tree_iter = widget.get_active_iter()
        if tree_iter is not None:
            model = widget.get_model()
            mode = model[tree_iter][1]
            self.set_onechar_mode(
                mode, update_gsettings=True)

    def _on_autoselect_mode_checkbutton(self, widget: Gtk.CheckButton) -> None:
        '''The checkbutton for autoselect mode has been clicked'''
        self.set_autoselect_mode(widget.get_active(), update_gsettings=True)

    def _on_autocommit_mode_combobox_changed(
            self, widget: Gtk.ComboBox) -> None:
        '''
        A change of the autocommit mode has been requested
        with the combobox
        '''
        tree_iter = widget.get_active_iter()
        if tree_iter is not None:
            model = widget.get_model()
            mode = model[tree_iter][1]
            self.set_autocommit_mode(
                mode, update_gsettings=True)

    def _on_commit_invalid_mode_combobox_changed(self, widget: Gtk.ComboBox) -> None:
        '''
        A change of the commit invalid mode has been requested
        with the combobox
        '''
        tree_iter = widget.get_active_iter()
        if tree_iter is not None:
            model = widget.get_model()
            commit_invalid_mode = model[tree_iter][1]
            self.set_commit_invalid_mode(
                commit_invalid_mode, update_gsettings=True)

    def _on_autowildcard_mode_checkbutton(
            self, widget: Gtk.CheckButton) -> None:
        '''The checkbutton for autocommit mode has been clicked'''
        self.set_autowildcard_mode(widget.get_active(), update_gsettings=True)

    def _on_table_full_width_letter_mode_combobox_changed(
            self, widget: Gtk.ComboBox) -> None:
        '''
        A change of the letter width when in “Table input” mode has been
        requested with the combobox
        '''
        tree_iter = widget.get_active_iter()
        if tree_iter is not None:
            model = widget.get_model()
            mode = model[tree_iter][1]
            self.set_table_full_width_letter_mode(
                mode, update_gsettings=True)

    def _on_table_full_width_punct_mode_combobox_changed(
            self, widget: Gtk.ComboBox) -> None:
        '''
        A change of the letter width when in “Table input” mode has been
        requested with the combobox
        '''
        tree_iter = widget.get_active_iter()
        if tree_iter is not None:
            model = widget.get_model()
            mode = model[tree_iter][1]
            self.set_table_full_width_punct_mode(
                mode, update_gsettings=True)

    def _on_direct_full_width_letter_mode_combobox_changed(
            self, widget: Gtk.ComboBox) -> None:
        '''
        A change of the letter width when in “Direct input” mode has been
        requested with the combobox
        '''
        tree_iter = widget.get_active_iter()
        if tree_iter is not None:
            model = widget.get_model()
            mode = model[tree_iter][1]
            self.set_direct_full_width_letter_mode(
                mode, update_gsettings=True)

    def _on_direct_full_width_punct_mode_combobox_changed(
            self, widget: Gtk.ComboBox) -> None:
        '''
        A change of the letter width when in “Direct input” mode has been
        requested with the combobox
        '''
        tree_iter = widget.get_active_iter()
        if tree_iter is not None:
            model = widget.get_model()
            mode = model[tree_iter][1]
            self.set_direct_full_width_punct_mode(
                mode, update_gsettings=True)

    def _on_always_show_lookup_checkbutton(
            self, widget: Gtk.CheckButton) -> None:
        '''The checkbutton for always show lookup has been clicked'''
        self.set_always_show_lookup(widget.get_active(), update_gsettings=True)

    def _on_use_dark_theme_checkbutton(self, widget: Gtk.CheckButton) -> None:
        '''The checkbutton for the dark theme has been clicked'''
        self.set_dark_theme(widget.get_active(), update_gsettings=True)

    def _on_dynamic_adjust_checkbutton(self, widget: Gtk.CheckButton) -> None:
        '''
        The checkbutton whether to dynamically adjust the candidates

        :param widget: The check button clicked
        '''
        self.set_dynamic_adjust(widget.get_active(), update_gsettings=True)

    def _on_dynamic_adjust_forget_button(
            self, _widget: Gtk.Button) -> None:
        '''
        The button to select forget how often candidates were used
        '''
        self._dynamic_adjust_forget_button.set_sensitive(False)
        response = self._run_are_you_sure_dialog(
            # Translators: This is the text in the centre of a small
            # dialog window, trying to confirm whether the user is
            # really sure to to delete all the data
            # ibus-table has learned from typing and selecting candidates.
            # Deleting this learned data cannot be reversed. So
            # the user should be really sure he really wants to do that.
            _('Do you really want to delete all '
              + 'data learned from typing and selecting candidates?'))
        if response == Gtk.ResponseType.OK:
            self.tabsqlitedb.remove_all_phrases_from_user_db()
        self._dynamic_adjust_forget_button.set_sensitive(True)

    def _on_error_sound_checkbutton(self, widget: Gtk.CheckButton) -> None:
        '''
        The checkbutton whether to play a sound file on error.

        :param widget: The check button clicked
        '''
        self.set_error_sound(widget.get_active(), update_gsettings=True)

    def _on_error_sound_file_button(
            self, _widget: Gtk.Button) -> None:
        '''
        The button to select the .wav sound file to be played on error.
        '''
        self._error_sound_file_button.set_sensitive(False)
        filename = ''
        chooser = Gtk.FileChooserDialog(
            title=_('Select .wav sound file:'),
            parent=self,
            action=Gtk.FileChooserAction.OPEN)
        chooser.add_button(_('_Cancel'), Gtk.ResponseType.CANCEL)
        chooser.add_button(_('_OK'), Gtk.ResponseType.OK)
        chooser.set_current_folder(os.path.dirname(
            self._settings_dict['errorsoundfile']['user']))
        response = chooser.run()
        if response == Gtk.ResponseType.OK:
            filename = chooser.get_filename()
        chooser.destroy()
        while Gtk.events_pending():
            Gtk.main_iteration()
        if filename:
            self._error_sound_file_button_label.set_text(
                filename)
            self.set_error_sound_file(
                filename, update_gsettings=True)
        self._error_sound_file_button.set_sensitive(True)

    def _on_debug_level_adjustment_value_changed(
            self, _widget: Gtk.SpinButton) -> None:
        '''The value for the debug level has been changed.'''
        self.set_debug_level(
            self._debug_level_adjustment.get_value(),
            update_gsettings=True)

    def _on_keybindings_treeview_row_activated(
            self,
            _treeview: Gtk.TreeView,
            treepath: Gtk.TreePath,
            _treeviewcolumn: Gtk.TreeViewColumn) -> None:
        '''
        A row in the treeview listing the key bindings has been activated.

        :param treeview: The treeview listing the key bindings
        :param treepath: The path to the activated row
        :param treeviewcolumn: A column in the treeview listing the
                               key bindings
        '''
        model = self._keybindings_treeview_model
        iterator = model.get_iter(treepath)
        command = model[iterator][0]
        if command != self._keybindings_selected_command:
            # This should not happen, if a row is activated it should
            # already be selected,
            # i.e. on_keybindings_treeview_row_selected() should have
            # been called already and this should have set
            # self._keybindings_selected_command
            LOGGER.error(
                'Unexpected error, command = "%s" '
                'self._keybindings_selected_command = "%s"\n',
                command,
                self._keybindings_selected_command)
            return
        self._create_and_show_keybindings_edit_popover()

    def _on_keybindings_treeview_row_selected(
            self, selection: Gtk.TreeSelection) -> None:
        '''
        A row in the treeview listing the key bindings has been selected.
        '''
        (model, iterator) = selection.get_selected()
        if iterator:
            self._keybindings_selected_command = model[iterator][0]
            self._keybindings_default_button.set_sensitive(True)
            self._keybindings_edit_button.set_sensitive(True)
        else:
            # all rows have been unselected
            self._keybindings_selected_command = ''
            self._keybindings_default_button.set_sensitive(False)
            self._keybindings_edit_button.set_sensitive(False)

    def _on_keybindings_edit_listbox_row_selected(
            self, _listbox: Gtk.ListBox, listbox_row: Gtk.ListBoxRow) -> None:
        '''
        Signal handler for selecting one of the key bindings
        for a certain command

        :param _listbox: The list box used to select a key binding
        :type _listbox: Gtk.ListBox object
        :param listbox_row: A row containing a key binding
        :type listbox_row: Gtk.ListBoxRow object
        '''
        if  listbox_row:
            keybinding = listbox_row.get_child().get_text()
            index = listbox_row.get_index()
            user_keybindings = self._settings_dict['keybindings']['user']
            command = self._keybindings_selected_command
            if (keybinding and command
                and keybinding in user_keybindings[command]):
                self._keybindings_edit_popover_selected_keybinding = keybinding
                self._keybindings_edit_popover_selected_keybinding_index = (
                    index)
                if self._keybindings_edit_popover_remove_button:
                    self._keybindings_edit_popover_remove_button.set_sensitive(
                        True)
                if self._keybindings_edit_popover_up_button:
                    self._keybindings_edit_popover_up_button.set_sensitive(
                        index > 0)
                if self._keybindings_edit_popover_down_button:
                    self._keybindings_edit_popover_down_button.set_sensitive(
                        index < len(user_keybindings[command]) - 1)
                return
        # all rows have been unselected
        self._keybindings_edit_popover_selected_keybinding = ''
        self._keybindings_edit_popover_selected_keybinding_index = -1
        if self._keybindings_edit_popover_remove_button:
            self._keybindings_edit_popover_remove_button.set_sensitive(False)
        if self._keybindings_edit_popover_up_button:
            self._keybindings_edit_popover_up_button.set_sensitive(False)
        if self._keybindings_edit_popover_down_button:
            self._keybindings_edit_popover_down_button.set_sensitive(False)

    def _on_keybindings_edit_popover_add_button_clicked(
            self, _button: Gtk.Button) -> None:
        '''
        Signal handler called when the “Add” button to add
        a key binding has been clicked.
        '''
        key_input_dialog = it_util.ItKeyInputDialog(parent=self)
        response = key_input_dialog.run()
        key_input_dialog.destroy()
        if response == Gtk.ResponseType.OK:
            keyval, state = key_input_dialog.e
            key = it_util.KeyEvent(keyval, 0, state)
            keybinding = it_util.keyevent_to_keybinding(key)
            command = self._keybindings_selected_command
            user_keybindings = self._settings_dict['keybindings']['user']
            if keybinding not in user_keybindings[command]:
                user_keybindings[command].append(keybinding)
                self._fill_keybindings_edit_popover_listbox()
                self.set_keybindings(user_keybindings)

    def _on_keybindings_edit_popover_remove_button_clicked(
            self, _button: Gtk.Button) -> None:
        '''
        Signal handler called when the “Remove” button to remove
        a key binding has been clicked.
        '''
        keybinding = self._keybindings_edit_popover_selected_keybinding
        command = self._keybindings_selected_command
        user_keybindings = self._settings_dict['keybindings']['user']
        if (keybinding and command
                and keybinding in user_keybindings[command]):
            user_keybindings[command].remove(keybinding)
            self._fill_keybindings_edit_popover_listbox()
            self.set_keybindings(user_keybindings)

    def _on_keybindings_edit_popover_up_button_clicked(
            self, _button: Gtk.Button) -> None:
        '''
        Signal handler called when the “up” button to move
        a key binding up has been clicked.
        '''
        index = self._keybindings_edit_popover_selected_keybinding_index
        command = self._keybindings_selected_command
        keybinding = self._keybindings_edit_popover_selected_keybinding
        user_keybindings = self._settings_dict['keybindings']['user']
        if not 0 < index < len(user_keybindings[command]):
            # This should not happen, one should not be able
            # to click the up button in this case, just return
            return
        user_keybindings[command] = (
            user_keybindings[command][:index - 1]
            + [user_keybindings[command][index]]
            + [user_keybindings[command][index - 1]]
            + user_keybindings[command][index + 1:])
        self.set_keybindings(user_keybindings, update_gsettings=True)
        self._fill_keybindings_edit_popover_listbox()
        self._keybindings_edit_popover_selected_keybinding_index = index - 1
        self._keybindings_edit_popover_selected_keybinding = keybinding
        if self._keybindings_edit_popover_listbox:
            self._keybindings_edit_popover_listbox.select_row(
                self._keybindings_edit_popover_listbox.get_row_at_index(
                    index - 1))

    def _on_keybindings_edit_popover_down_button_clicked(
            self, _button: Gtk.Button) -> None:
        '''
        Signal handler called when the “down” button to move
        a key binding down has been clicked.
        '''
        index = self._keybindings_edit_popover_selected_keybinding_index
        command = self._keybindings_selected_command
        keybinding = self._keybindings_edit_popover_selected_keybinding
        user_keybindings = self._settings_dict['keybindings']['user']
        if not 0 <= index < len(user_keybindings[command]) - 1:
            # This should not happen, one should not be able
            # to click the up button in this case, just return
            return
        user_keybindings[command] = (
            user_keybindings[command][:index]
            + [user_keybindings[command][index + 1]]
            + [user_keybindings[command][index]]
            + user_keybindings[command][index + 2:])
        self.set_keybindings(user_keybindings, update_gsettings=True)
        self._fill_keybindings_edit_popover_listbox()
        self._keybindings_edit_popover_selected_keybinding_index = index + 1
        self._keybindings_edit_popover_selected_keybinding = keybinding
        if self._keybindings_edit_popover_listbox:
            self._keybindings_edit_popover_listbox.select_row(
                self._keybindings_edit_popover_listbox.get_row_at_index(
                    index + 1))

    def _on_keybindings_edit_popover_default_button_clicked(
            self, _button: Gtk.Button) -> None:
        '''
        Signal handler called when the “Default” button to set
        the keybindings to the default has been clicked.
        '''
        default_keybindings = self._settings_dict['keybindings']['default']
        user_keybindings = self._settings_dict['keybindings']['user']
        command = self._keybindings_selected_command
        if command and command in default_keybindings:
            user_keybindings[command] = default_keybindings[command].copy()
            self._fill_keybindings_edit_popover_listbox()
            self.set_keybindings(user_keybindings)

    def _fill_keybindings_edit_popover_listbox(self) -> None:
        '''
        Fill the edit listbox to with the key bindings of the currently
        selected command
        '''
        if self._keybindings_edit_popover_scroll is None:
            LOGGER.debug('self._keybindings_edit_popover_scroll is None')
            return
        for child in self._keybindings_edit_popover_scroll.get_children():
            self._keybindings_edit_popover_scroll.remove(child)
        self._keybindings_edit_popover_listbox = Gtk.ListBox()
        self._keybindings_edit_popover_scroll.add(
            self._keybindings_edit_popover_listbox)
        self._keybindings_edit_popover_selected_keybinding = ''
        self._keybindings_edit_popover_selected_keybinding_index = -1
        self._keybindings_edit_popover_listbox.set_visible(True)
        self._keybindings_edit_popover_listbox.set_vexpand(True)
        self._keybindings_edit_popover_listbox.set_selection_mode(
            Gtk.SelectionMode.SINGLE)
        self._keybindings_edit_popover_listbox.set_activate_on_single_click(
            True)
        self._keybindings_edit_popover_listbox.connect(
            'row-selected', self._on_keybindings_edit_listbox_row_selected)
        user_keybindings = self._settings_dict['keybindings']['user']
        for keybinding in user_keybindings[self._keybindings_selected_command]:
            label = Gtk.Label()
            label.set_text(html.escape(keybinding))
            label.set_use_markup(True)
            label.set_xalign(0)
            margin = 1
            label.set_margin_start(margin)
            label.set_margin_end(margin)
            label.set_margin_top(margin)
            label.set_margin_bottom(margin)
            self._keybindings_edit_popover_listbox.insert(label, -1)
        self._keybindings_edit_popover_remove_button.set_sensitive(False)
        self._keybindings_edit_popover_up_button.set_sensitive(False)
        self._keybindings_edit_popover_down_button.set_sensitive(False)
        self._keybindings_edit_popover_listbox.show_all()

    def _create_and_show_keybindings_edit_popover(self) -> None:
        '''
        Create and show the popover to edit the key bindings for a command
        '''
        self._keybindings_edit_popover = Gtk.Popover()
        if self._keybindings_edit_popover is None:
            LOGGER.debug('self._keybindings_edit_popover is None')
            return
        self._keybindings_edit_popover.set_relative_to(
            self._keybindings_edit_button)
        self._keybindings_edit_popover.set_position(Gtk.PositionType.RIGHT)
        self._keybindings_edit_popover.set_vexpand(True)
        self._keybindings_edit_popover.set_hexpand(True)
        keybindings_edit_popover_vbox = Gtk.Box()
        keybindings_edit_popover_vbox.set_orientation(
            Gtk.Orientation.VERTICAL)
        margin = 12
        keybindings_edit_popover_vbox.set_margin_start(margin)
        keybindings_edit_popover_vbox.set_margin_end(margin)
        keybindings_edit_popover_vbox.set_margin_top(margin)
        keybindings_edit_popover_vbox.set_margin_bottom(margin)
        keybindings_edit_popover_vbox.set_spacing(margin)
        keybindings_edit_popover_label = Gtk.Label()
        keybindings_edit_popover_label.set_text(
            _('Edit key bindings for command “%s”')
            %self._keybindings_selected_command)
        keybindings_edit_popover_label.set_use_markup(True)
        keybindings_edit_popover_label.set_visible(True)
        keybindings_edit_popover_label.set_halign(Gtk.Align.FILL)
        keybindings_edit_popover_vbox.pack_start(
            keybindings_edit_popover_label, False, False, 0)
        self._keybindings_edit_popover_scroll = Gtk.ScrolledWindow()
        self._keybindings_edit_popover_scroll.set_hexpand(True)
        self._keybindings_edit_popover_scroll.set_vexpand(True)
        self._keybindings_edit_popover_scroll.set_kinetic_scrolling(False)
        self._keybindings_edit_popover_scroll.set_overlay_scrolling(True)
        keybindings_edit_popover_vbox.pack_start(
            self._keybindings_edit_popover_scroll, True, True, 0)
        keybindings_edit_popover_button_box = Gtk.Box()
        keybindings_edit_popover_button_box.set_orientation(
            Gtk.Orientation.HORIZONTAL)
        keybindings_edit_popover_button_box.set_can_focus(False)
        keybindings_edit_popover_vbox.add(
            keybindings_edit_popover_button_box)
        self._keybindings_edit_popover_add_button = Gtk.Button()
        keybindings_edit_popover_add_button_label = Gtk.Label()
        keybindings_edit_popover_add_button_label.set_text(
            '<span size="xx-large"><b>+</b></span>')
        keybindings_edit_popover_add_button_label.set_use_markup(True)
        self._keybindings_edit_popover_add_button.add(
            keybindings_edit_popover_add_button_label)
        self._keybindings_edit_popover_add_button.set_tooltip_text(
            # Translators: This is a tooltip for the button to add a
            # key binding.
            _('Add a key binding'))
        self._keybindings_edit_popover_add_button.connect(
            'clicked', self._on_keybindings_edit_popover_add_button_clicked)
        self._keybindings_edit_popover_add_button.set_sensitive(True)
        self._keybindings_edit_popover_remove_button = Gtk.Button()
        keybindings_edit_popover_remove_button_label = Gtk.Label()
        keybindings_edit_popover_remove_button_label.set_text(
            '<span size="xx-large"><b>-</b></span>')
        keybindings_edit_popover_remove_button_label.set_use_markup(True)
        self._keybindings_edit_popover_remove_button.add(
            keybindings_edit_popover_remove_button_label)
        self._keybindings_edit_popover_remove_button.set_tooltip_text(
            # Translators: This is a tooltip for the button to remove
            # the selected key binding.
            _('Remove selected key binding'))
        self._keybindings_edit_popover_remove_button.connect(
            'clicked', self._on_keybindings_edit_popover_remove_button_clicked)
        self._keybindings_edit_popover_remove_button.set_sensitive(False)
        self._keybindings_edit_popover_default_button = Gtk.Button()
        self._keybindings_edit_popover_up_button = Gtk.Button()
        keybindings_edit_popover_up_button_label = Gtk.Label()
        keybindings_edit_popover_up_button_label.set_text(
            '<span size="xx-large"><b>↑</b></span>')
        keybindings_edit_popover_up_button_label.set_use_markup(True)
        self._keybindings_edit_popover_up_button.add(
            keybindings_edit_popover_up_button_label)
        self._keybindings_edit_popover_up_button.set_tooltip_text(
            # Translators: This is a tooltip for the button to move
            # the selected key binding up (higher in priority).
            _('Move key binding up'))
        self._keybindings_edit_popover_up_button.connect(
            'clicked', self._on_keybindings_edit_popover_up_button_clicked)
        self._keybindings_edit_popover_down_button = Gtk.Button()
        keybindings_edit_popover_down_button_label = Gtk.Label()
        keybindings_edit_popover_down_button_label.set_text(
            '<span size="xx-large"><b>↓</b></span>')
        keybindings_edit_popover_down_button_label.set_use_markup(True)
        self._keybindings_edit_popover_down_button.add(
            keybindings_edit_popover_down_button_label)
        self._keybindings_edit_popover_down_button.set_tooltip_text(
            # Translators: This is a tooltip for the button to move
            # the selected key binding down (lower in priority).
            _('Move key binding down'))
        self._keybindings_edit_popover_down_button.connect(
            'clicked', self._on_keybindings_edit_popover_down_button_clicked)
        keybindings_edit_popover_default_button_label = Gtk.Label()
        keybindings_edit_popover_default_button_label.set_text(
            _('Set to default'))
        keybindings_edit_popover_default_button_label.set_use_markup(True)
        self._keybindings_edit_popover_default_button.add(
            keybindings_edit_popover_default_button_label)
        self._keybindings_edit_popover_default_button.set_tooltip_text(
            # Translators: This is a tooltip for the button to set
            # the key bindings for the selected command to the default.
            _('Set default key bindings for the selected command'))
        self._keybindings_edit_popover_default_button.connect(
            'clicked',
            self._on_keybindings_edit_popover_default_button_clicked)
        self._keybindings_edit_popover_default_button.set_sensitive(True)
        keybindings_edit_popover_button_box.add(
            self._keybindings_edit_popover_add_button)
        keybindings_edit_popover_button_box.add(
            self._keybindings_edit_popover_remove_button)
        keybindings_edit_popover_button_box.add(
            self._keybindings_edit_popover_up_button)
        keybindings_edit_popover_button_box.add(
            self._keybindings_edit_popover_down_button)
        keybindings_edit_popover_button_box.add(
            self._keybindings_edit_popover_default_button)
        self._keybindings_edit_popover.add(keybindings_edit_popover_vbox)
        self._fill_keybindings_edit_popover_listbox()
        if GTK_VERSION >= (3, 22, 0):
            self._keybindings_edit_popover.popup()
        self._keybindings_edit_popover.show_all()

    def _on_keybindings_edit_button_clicked(
            self, _button: Gtk.Button) -> None:
        '''
        Signal handler called when the “edit” button to edit the
        key bindings for a command has been clicked.
        '''
        self._create_and_show_keybindings_edit_popover()

    def _on_keybindings_default_button_clicked(
            self, _button: Gtk.Button) -> None:
        '''
        Signal handler called when the “Set to default” button to reset the
        key bindings for a command to the default has been clicked.
        '''
        default_keybindings = self._settings_dict['keybindings']['default']
        user_keybindings = self._settings_dict['keybindings']['user']
        command = self._keybindings_selected_command
        if command and command in default_keybindings:
            user_keybindings[command] = default_keybindings[command].copy()
            self.set_keybindings(user_keybindings)

    def _on_keybindings_all_default_button_clicked(
            self, _button: Gtk.Button) -> None:
        '''
        Signal handler called when the “Set all to default” button to reset the
        all key bindings top their defaults has been clicked.
        '''
        self._keybindings_all_default_button.set_sensitive(False)
        response = self._run_are_you_sure_dialog(
            # Translators: This is the text in the centre of a small
            # dialog window, trying to confirm whether the user is
            # really sure to reset the key bindings for *all* commands
            # to their defaults. This cannot be reversed so the user
            # should be really sure he wants to do that.
            _('Do you really want to set the key bindings for '
              + 'all commands to their defaults?'))
        if response == Gtk.ResponseType.OK:
            self.set_keybindings(self._settings_dict['keybindings']['default'])
        self._keybindings_all_default_button.set_sensitive(True)

    def _on_input_method_menu_checkbutton(self, _widget: Gtk.CheckButton) -> None:
        '''
        The checkbutton to whether to display the input method menu item

        :param widget: The check button clicked
        '''
        items = []
        for item in self._input_method_menu_tuple:
            name, _label, button = item
            if isinstance(button, Gtk.CheckButton) and button.get_active():
                items.append(str(name))
        self.set_input_method_menu(items, update_gsettings=True)

    def set_single_wildcard_char(self,
                                 single_wildcard_char: str,
                                 update_gsettings: bool = True) -> None:
        '''Sets the single wildchard character.

        :param single_wildcard_char: The character to use as a single wildcard
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)',
            single_wildcard_char, update_gsettings)
        self._settings_dict['singlewildcardchar']['user'] = (
            single_wildcard_char)
        if update_gsettings:
            self._gsettings.set_value(
                'singlewildcardchar',
                GLib.Variant.new_string(single_wildcard_char))
        else:
            self._single_wildcard_char_entry.set_text(single_wildcard_char)

    def set_multi_wildcard_char(self,
                                multi_wildcard_char: str,
                                update_gsettings: bool = True) -> None:
        '''Sets the single wildchard character.

        :param multi_wildcard_char: The character to use as a single wildcard
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)',
            multi_wildcard_char, update_gsettings)
        self._settings_dict['multiwildcardchar']['user'] = multi_wildcard_char
        if update_gsettings:
            self._gsettings.set_value(
                'multiwildcardchar',
                GLib.Variant.new_string(multi_wildcard_char))
        else:
            self._multi_wildcard_char_entry.set_text(multi_wildcard_char)

    def set_page_size(self,
                      page_size: int,
                      update_gsettings: bool = True) -> None:
        '''Sets the page size of the lookup table

        :param page_size: The page size of the lookup table
                          (1 <= page size <= 10)
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', page_size, update_gsettings)
        page_size = int(page_size)
        if 1 <= page_size <= 10:
            self._settings_dict['lookuptablepagesize']['user'] = page_size
            if update_gsettings:
                self._gsettings.set_value(
                    'lookuptablepagesize',
                    GLib.Variant.new_int32(page_size))
            else:
                self._page_size_adjustment.set_value(page_size)

    def set_lookup_table_orientation(self,
                                     orientation: int,
                                     update_gsettings: bool = True) -> None:
        '''Sets the page size of the lookup table

        :param orientation: The orientation of the lookup table
                            (0 < =orientation <= 2)
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', orientation, update_gsettings)
        orientation = int(orientation)
        if 0 <= orientation <= 2:
            self._settings_dict['lookuptableorientation']['user'] = orientation
            if update_gsettings:
                self._gsettings.set_value(
                    'lookuptableorientation',
                    GLib.Variant.new_int32(orientation))
            else:
                for index, item in enumerate(
                        self._lookup_table_orientation_store):
                    if orientation == item[1]:
                        self._lookup_table_orientation_combobox.set_active(
                            index)

    def set_input_mode(self,
                       input_mode: int = 1,
                       update_gsettings: bool = True) -> None:
        '''Sets whether direct input or the current table is used.

        :param input_mode: Whether to use direct input.
                           0: Use direct input.
                           1: Use the current table.
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', input_mode, update_gsettings)
        input_mode = int(input_mode)
        if 0 <= input_mode <= 1:
            self._settings_dict['inputmode']['user'] = input_mode
            if update_gsettings:
                self._gsettings.set_value(
                    'inputmode',
                    GLib.Variant.new_int32(input_mode))

    def set_remember_input_mode(self,
                                remember_input_mode: bool = True,
                                update_gsettings: bool = True) -> None:
        '''Sets whether the input mode (direct or table) is remembered

        :param remember_input_mode: Whether to remember the input mode.
                                    False: Do not remember
                                    True:  Remember.
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', remember_input_mode, update_gsettings)
        remember_input_mode = bool(remember_input_mode)
        self._settings_dict['rememberinputmode']['user'] = remember_input_mode
        if update_gsettings:
            self._gsettings.set_value(
                'rememberinputmode',
                GLib.Variant.new_boolean(remember_input_mode))
        else:
            for index, item in enumerate(self._remember_input_mode_store):
                if remember_input_mode == item[1]:
                    self._remember_input_mode_combobox.set_active(index)

    def set_chinese_mode(self,
                         chinese_mode: int = 0,
                         update_gsettings: bool = True) -> None:
        '''Sets the candidate filter mode used for Chinese

        0 means to show simplified Chinese only
        1 means to show traditional Chinese only
        2 means to show all characters but show simplified Chinese first
        3 means to show all characters but show traditional Chinese first
        4 means to show all characters

        :param chinese_mode: The Chinese filter mode (0 <= mode <= 4)
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the dconf key changed
                                 to avoid endless loops when the dconf
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', chinese_mode, update_gsettings)
        chinese_mode = int(chinese_mode)
        if 0 <= chinese_mode <= 4:
            self._settings_dict['chinesemode']['user'] = chinese_mode
            if update_gsettings:
                self._gsettings.set_value(
                    'chinesemode',
                    GLib.Variant.new_int32(chinese_mode))
            else:
                for index, item in enumerate(self._chinese_mode_store):
                    if chinese_mode == item[1]:
                        self._chinese_mode_combobox.set_active(index)

    def set_onechar_mode(self,
                         mode: bool = False,
                         update_gsettings: bool = True) -> None:
        '''Sets whether only single characters should be matched in
        the database.

        :param mode: Whether only single characters should be matched.
                     True: Match only single characters.
                     False: Possibly match multiple characters at once.
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', mode, update_gsettings)
        mode = bool(mode)
        self._settings_dict['onechar']['user'] = mode
        if update_gsettings:
            self._gsettings.set_value(
                'onechar',
                GLib.Variant.new_boolean(mode))
        else:
            for index, item in enumerate(self._onechar_mode_store):
                if mode == item[1]:
                    self._onechar_mode_combobox.set_active(index)

    def set_autoselect_mode(self,
                            mode: bool = False,
                            update_gsettings: bool = True) -> None:
        '''Sets whether the first candidate will be selected
        automatically during typing.

        :param mode: Whether to select the first candidate automatically.
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', mode, update_gsettings)
        mode = bool(mode)
        self._settings_dict['autoselect']['user'] = mode
        if update_gsettings:
            self._gsettings.set_value(
                'autoselect',
                GLib.Variant.new_boolean(mode))
        else:
            self._autoselect_mode_checkbutton.set_active(mode)

    def set_autocommit_mode(self,
                            mode: bool = False,
                            update_gsettings: bool = True) -> None:
        '''Sets whether automatic commits go into the preëdit or into the
        application.

        :param mode: Whether automatic commits  go into the  preëdit
                     or into the application.
                     True: Into the application.
                     False: Into the preedit.
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', mode, update_gsettings)
        mode = bool(mode)
        self._settings_dict['autocommit']['user'] = mode
        if update_gsettings:
            self._gsettings.set_value(
                'autocommit',
                GLib.Variant.new_boolean(mode))
        else:
            for index, item in enumerate(self._autocommit_mode_store):
                if mode == item[1]:
                    self._autocommit_mode_combobox.set_active(index)

    def set_commit_invalid_mode(self,
                         mode: int = 0,
                         update_gsettings: bool = True) -> None:
        '''Sets the commit invalid mode

        This selects what is committed when a character which is not
        in the set of valid input characters for the current table is
        typed.

        0 means to commit the current candidate
        1 means to commit the raw characters typed so far

        :param mode:             The mode (0 <= mode <= 1)
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the dconf key changed
                                 to avoid endless loops when the dconf
                                 key is changed twice in a short time.

        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', mode, update_gsettings)
        mode = int(mode)
        if 0 <= mode <= 1:
            self._settings_dict['commitinvalidmode']['user'] = mode
            if update_gsettings:
                self._gsettings.set_value(
                    'commitinvalidmode',
                    GLib.Variant.new_int32(mode))
            else:
                for index, item in enumerate(self._commit_invalid_mode_store):
                    if mode == item[1]:
                        self._commit_invalid_mode_combobox.set_active(index)

    def set_autowildcard_mode(self,
                              mode: bool = False,
                              update_gsettings: bool = True) -> None:
        '''Sets whether a wildcard should be automatically appended
        to the input.

        :param mode: Whether to append a wildcard automatically.
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', mode, update_gsettings)
        mode = bool(mode)
        self._settings_dict['autowildcard']['user'] = mode
        if update_gsettings:
            self._gsettings.set_value(
                'autowildcard',
                GLib.Variant.new_boolean(mode))
        else:
            self._autowildcard_mode_checkbutton.set_active(mode)

    def set_table_full_width_letter_mode(
            self,
            mode: bool =False,
            update_gsettings: bool = True) -> None:
        '''Sets whether full width letters should be used
        while in “Table input” mode

        :param mode: Whether to use full width letters
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', mode, update_gsettings)
        mode = bool(mode)
        self._settings_dict['tabdeffullwidthletter']['user'] = mode
        if update_gsettings:
            self._gsettings.set_value(
                'tabdeffullwidthletter',
                GLib.Variant.new_boolean(mode))
        else:
            for index, item in enumerate(
                    self._table_full_width_letter_mode_store):
                if mode == item[1]:
                    self._table_full_width_letter_mode_combobox.set_active(
                        index)

    def set_table_full_width_punct_mode(
            self,
            mode: bool = False,
            update_gsettings: bool = True) -> None:
        '''Sets whether full width punctuation should be used
        while in “Table input” mode

        :param mode: Whether to use full width punctuation
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', mode, update_gsettings)
        mode = bool(mode)
        self._settings_dict['tabdeffullwidthpunct']['user'] = mode
        if update_gsettings:
            self._gsettings.set_value(
                'tabdeffullwidthpunct',
                GLib.Variant.new_boolean(mode))
        else:
            for index, item in enumerate(
                    self._table_full_width_punct_mode_store):
                if mode == item[1]:
                    self._table_full_width_punct_mode_combobox.set_active(
                        index)

    def set_direct_full_width_letter_mode(
            self,
            mode: bool = False,
            update_gsettings: bool = True) -> None:
        '''Sets whether full width letters should be used
        while in “Direct input” mode

        :param mode: Whether to use full width letters
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', mode, update_gsettings)
        mode = bool(mode)
        self._settings_dict['endeffullwidthletter']['user'] = mode
        if update_gsettings:
            self._gsettings.set_value(
                'endeffullwidthletter',
                GLib.Variant.new_boolean(mode))
        else:
            for index, item in enumerate(
                    self._direct_full_width_letter_mode_store):
                if mode == item[1]:
                    self._direct_full_width_letter_mode_combobox.set_active(
                        index)

    def set_direct_full_width_punct_mode(
            self,
            mode: bool = False,
            update_gsettings: bool = True) -> None:
        '''Sets whether full width punctuation should be used
        while in “Direct input” mode

        :param mode: Whether to use full width punctuation
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', mode, update_gsettings)
        mode = bool(mode)
        self._settings_dict['endeffullwidthpunct']['user'] = mode
        if update_gsettings:
            self._gsettings.set_value(
                'endeffullwidthpunct',
                GLib.Variant.new_boolean(mode))
        else:
            for index, item in enumerate(
                    self._direct_full_width_punct_mode_store):
                if mode == item[1]:
                    self._direct_full_width_punct_mode_combobox.set_active(
                        index)

    def set_always_show_lookup(
            self,
            mode: bool = False,
            update_gsettings: bool = True) -> None:
        '''Sets the whether the lookup table is shown.

        :param mode: Whether to show the lookup table
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', mode, update_gsettings)
        self._settings_dict['alwaysshowlookup']['user'] = mode
        if update_gsettings:
            self._gsettings.set_value(
                'alwaysshowlookup',
                GLib.Variant.new_boolean(mode))
        else:
            self._always_show_lookup_checkbutton.set_active(mode)

    def set_dark_theme(
            self,
            use_dark_theme: bool = False,
            update_gsettings: bool = True) -> None:
        '''Sets the whether to use the color scheme for dark theme.

        :param use_dark_theme: Whether to use the color scheme for dark theme
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', use_dark_theme, update_gsettings)
        self._settings_dict['darktheme']['user'] = use_dark_theme
        if update_gsettings:
            self._gsettings.set_value(
                'darktheme',
                GLib.Variant.new_boolean(use_dark_theme))
        else:
            self._use_dark_theme_checkbutton.set_active(use_dark_theme)

    def set_dynamic_adjust(
            self,
            dynamic_adjust: bool,
            update_gsettings: bool = True) -> None:
        '''Sets the whether dynamically adjust the candidates according to
        how often they are used.

        :param dynamic_adjust: Whether to dynamically adjust the candidates
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', dynamic_adjust, update_gsettings)
        self._settings_dict['dynamicadjust']['user'] = dynamic_adjust
        if update_gsettings:
            self._gsettings.set_value(
                'dynamicadjust',
                GLib.Variant.new_boolean(dynamic_adjust))
        else:
            self._dynamic_adjust_checkbutton.set_active(dynamic_adjust)

    def set_error_sound(
            self,
            error_sound: bool,
            update_gsettings: bool = True) -> None:
        '''Sets the whether to play a sound on error.

        :param error_sound: Whether to play a sound on error
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', error_sound, update_gsettings)
        self._settings_dict['errorsound']['user'] = error_sound
        if update_gsettings:
            self._gsettings.set_value(
                'errorsound',
                GLib.Variant.new_boolean(error_sound))
        else:
            self._error_sound_checkbutton.set_active(error_sound)

    def set_error_sound_file(
            self,
            path: Union[str, Any],
            update_gsettings: bool = True) -> None:
        '''Sets the path of file containing the sound to play on error.

        :param path: Full path of the .wav file containing the error sound.
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', path, update_gsettings)
        if not isinstance(path, str):
            return
        self._settings_dict['errorsoundfile']['user'] = path
        if update_gsettings:
            self._gsettings.set_value(
                'errorsoundfile',
                GLib.Variant.new_string(path))
        else:
            self._error_sound_file_button_label.set_text(path)
        self._error_sound_object = it_sound.SoundObject(
            os.path.expanduser(self._settings_dict['errorsoundfile']['user']),
            audio_backend=self._settings_dict['soundbackend']['user'])
        if self._error_sound_object:
            try:
                self._error_sound_object.play()
            except Exception as error: # pylint: disable=broad-except
                LOGGER.exception('Playing error sound failed: %s: %s',
                                 error.__class__.__name__, error)

    def set_sound_backend(
            self,
            sound_backend: Union[str, Any],
            update_gsettings: bool = True) -> None:
        '''Sets the sound backend to use

        :param sound_backend: The name of sound backend to use
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the dconf key changed
                                 to avoid endless loops when the dconf
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', sound_backend, update_gsettings)
        if not isinstance(sound_backend, str):
            return
        if sound_backend == self._settings_dict['soundbackend']['user']:
            return
        self._settings_dict['soundbackend']['user'] = sound_backend
        if update_gsettings:
            self._gsettings.set_value(
                'soundbackend',
                GLib.Variant.new_string(sound_backend))
        self._error_sound_object = it_sound.SoundObject(
            os.path.expanduser(self._settings_dict['errorsoundfile']['user']),
            audio_backend=self._settings_dict['soundbackend']['user'])

    def set_debug_level(self,
                        debug_level: int,
                        update_gsettings: bool = True) -> None:
        '''Sets the debug level

        :param debug level: The debug level (0 <= level <= 255)
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', debug_level, update_gsettings)
        debug_level = int(debug_level)
        if 0 <= debug_level <= 255:
            self._settings_dict['debuglevel']['user'] = debug_level
            if update_gsettings:
                self._gsettings.set_value(
                    'debuglevel',
                    GLib.Variant.new_int32(debug_level))
            else:
                self._debug_level_adjustment.set_value(debug_level)

    def set_keybindings(
            self,
            keybindings: Union[Dict[str, List[str]], Any],
            update_gsettings: bool = True) -> None:
        '''Set current key bindings

        :param keybindings: The key bindings to use
                            Commands which do not already
                            exist in the current key bindings dictionary
                            will be ignored.
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', keybindings, update_gsettings)
        if not isinstance(keybindings, dict):
            return
        keybindings = copy.deepcopy(keybindings)
        user_keybindings = self._settings_dict['keybindings']['user']
        # Update the default settings with the possibly changed settings:
        it_util.dict_update_existing_keys(user_keybindings, keybindings)
        # update the tree model
        model = self._keybindings_treeview_model
        iterator = model.get_iter_first()
        while iterator:
            for command in user_keybindings:
                if model.get_value(iterator, 0) == command:
                    model.set_value(iterator, 1,
                                    repr(user_keybindings[command]))
            iterator = model.iter_next(iterator)
        if update_gsettings:
            variant_dict = GLib.VariantDict(GLib.Variant('a{sv}', {}))
            for command in sorted(user_keybindings):
                variant_array = GLib.Variant.new_array(
                    GLib.VariantType('s'),
                    [GLib.Variant.new_string(x)
                     for x in user_keybindings[command]])
                variant_dict.insert_value(command, variant_array)
            self._gsettings.set_value(
                'keybindings',
                variant_dict.end())

    def set_input_method_menu(
            self,
            input_method_menu: List[str],
            update_gsettings: bool = True) -> None:
        '''Sets the visible input method menu items

        :param input_method_menu: The visible input method menu items
        :param update_gsettings: Whether to write the change to Gsettings.
                                 Set this to False if this method is
                                 called because the Gsettings key changed
                                 to avoid endless loops when the Gsettings
                                 key is changed twice in a short time.
        '''
        LOGGER.info(
            '(%s, update_gsettings = %s)', input_method_menu, update_gsettings)
        self._settings_dict['inputmethodmenu']['user'] = input_method_menu
        if update_gsettings:
            self._gsettings.set_value(
                'inputmethodmenu',
                GLib.Variant.new_strv(input_method_menu))
        else:
            for item in self._input_method_menu_tuple:
                name, _label, button = item
                if isinstance(button, Gtk.CheckButton):
                    if name in input_method_menu:
                        button.set_active(True)
                    else:
                        button.set_active(False)

class HelpWindow(Gtk.Window): # type: ignore
    '''
    A window to show help

    :param parent: The parent object
    :param title: Title of the help window
    :param contents: Contents of the help window
    '''
    def __init__(self,
                 parent: Gtk.Window = None,
                 title: str = '',
                 contents: str = '') -> None:
        Gtk.Window.__init__(self, title=title)
        if parent:
            self.set_parent(parent)
            self.set_transient_for(parent)
            # to receive mouse events for scrolling and for the close
            # button
            self.set_modal(True)
        self.set_destroy_with_parent(False)
        self.set_default_size(600, 500)
        self.vbox = Gtk.Box()
        self.vbox.set_orientation(Gtk.Orientation.VERTICAL)
        self.vbox.set_spacing(0)
        self.add(self.vbox)
        self.text_buffer = Gtk.TextBuffer()
        self.text_buffer.insert_at_cursor(contents)
        self.text_view = Gtk.TextView()
        self.text_view.set_buffer(self.text_buffer)
        self.text_view.set_editable(False)
        self.text_view.set_cursor_visible(False)
        self.text_view.set_justification(Gtk.Justification.LEFT)
        self.text_view.set_wrap_mode(Gtk.WrapMode.WORD)
        self.scrolledwindow = Gtk.ScrolledWindow()
        self.scrolledwindow.set_hexpand(True)
        self.scrolledwindow.set_vexpand(True)
        self.scrolledwindow.add(self.text_view)
        self.vbox.pack_start(self.scrolledwindow, True, True, 0)
        self.close_button = Gtk.Button()
        self.close_button_label = Gtk.Label()
        self.close_button_label.set_text_with_mnemonic(_('_Close'))
        self.close_button.add(self.close_button_label)
        self.close_button.connect("clicked", self._on_close_button_clicked)
        self.hbox = Gtk.HBox(spacing=0)
        self.hbox.pack_end(self.close_button, False, False, 0)
        self.vbox.pack_start(self.hbox, False, False, 5)
        self.show_all()

    def _on_close_button_clicked(self, _button: Gtk.Button) -> None:
        '''
        Close the input method help window when the close button is clicked
        '''
        self.destroy()

def quit_glib_main_loop(
        signum: int, _frame: Optional[FrameType] = None) -> None:
    '''Signal handler for signals from Python’s signal module

    :param signum: The signal number
    :param _frame:  Almost never used (it’s for debugging).
    '''
    if signum is not None:
        try:
            signal_name = signal.Signals(signum).name
        except ValueError: # In case signum isn't in Signals enum
            signal_name = str(signum)
        LOGGER.info('Received signal %s (%s), exiting...', signum, signal_name)
    if GLIB_MAIN_LOOP is not None:
        GLIB_MAIN_LOOP.quit()
    else:
        raise RuntimeError("GLIB_MAIN_LOOP not initialized!")

if __name__ == '__main__':
    if _ARGS.no_debug:
        LOG_HANDLER_NULL = logging.NullHandler()
    else:
        LOGFILE = os.path.join(
            ibus_table_location.cache_home(), 'setup-debug.log')
        LOG_HANDLER_TIME_ROTATE = logging.handlers.TimedRotatingFileHandler(
            LOGFILE,
            when='H',
            interval=6,
            backupCount=7,
            encoding='UTF-8',
            delay=False,
            utc=False,
            atTime=None)
        LOG_FORMATTER = logging.Formatter(
            '%(asctime)s %(filename)s '
            'line %(lineno)d %(funcName)s %(levelname)s: '
            '%(message)s')
        LOG_HANDLER_TIME_ROTATE.setFormatter(LOG_FORMATTER)
        LOGGER.setLevel(logging.DEBUG)
        LOGGER.addHandler(LOG_HANDLER_TIME_ROTATE)
        LOGGER.info('********** STARTING **********')

    try:
        locale.setlocale(locale.LC_ALL, '')
    except locale.Error:
        LOGGER.exception("IBUS-WARNING **: Using the fallback 'C' locale")
        locale.setlocale(locale.LC_ALL, 'C')
    i18n_init()
    if IBus.get_address() is None:
        DIALOG = Gtk.MessageDialog(
            modal=True,
            message_type=Gtk.MessageType.ERROR,
            buttons=Gtk.ButtonsType.OK,
            text=_('ibus is not running.'))
        DIALOG.run()
        DIALOG.destroy()
        sys.exit(1)
    ENGINE_NAME = _ARGS.engine_name
    if not ENGINE_NAME and 'IBUS_ENGINE_NAME' in os.environ:
        ENGINE_NAME = os.environ['IBUS_ENGINE_NAME']
    ENGINE_NAME = re.sub(r'^table:', '', ENGINE_NAME).replace(' ', '_')
    if not ENGINE_NAME:
        PARSER.print_help()
    SETUP_UI = SetupUI(engine_name=ENGINE_NAME)
    GLIB_MAIN_LOOP = GLib.MainLoop()
    signal.signal(signal.SIGTERM, quit_glib_main_loop) # kill <pid>
    # Ctrl+C (optional, can also use try/except KeyboardInterrupt)
    # signal.signal(signal.SIGINT, quit_glib_main_loop)
    try:
        GLIB_MAIN_LOOP.run()
    except KeyboardInterrupt:
        # SIGNINT (Control+C) received
        LOGGER.info('Control+C pressed, exiting ...')
        GLIB_MAIN_LOOP.quit()