Known problems:

If file system full and write to swap file failed, get error message for
	lnum > line_count?
When editing same file in two xterms, in second type ":" at first wait-return
	for ".swp file exists", at exit cursor is left at top of window.
Windows NT: display is not always correct.
Windows NT: CTRL-C in a child shell (created with ":sh" or CTRL-Z) kills Vim.
MSDOS: When using smardrive a readonly floppy will cause problems. Test for
	writable directory first?
Some terminals start inverting at the position where the invert code is put.
	This is not handled correctly. Remove 'weirdinvert' hack.
":s/\(.*\)/\1" on line with ^M should not replace ^M by linebreaks.
Replace with 'r' should set last inserted text.
BS in replace mode does not work correctly with et set and after inserting a TAB.
In insert mode CTRL-O . does not repeat the last CTRL-O command but the insertion.
Sometimes the time stamp in the memfile is old. May be caused by opening the 
	file r/w when testing for readonly.
When doing a CTRL-Z and typing a command for the shell, while Vim is busy
	(e.g. writing a file), the command for the shell is sometimes eaten by Vim.
Find out why screen size is changed in unexpected place for Bob Beresh.


To be checked:
Check '\n' at end of some : commands (that do not have TRLBAR).
Check for '\\' at the start of search commands (undocumented vi feature).
Environment name expansion for 'bdir' default value does not work?
Usage of isspace() vi-compatible (compared to iswhite())?
Terminal initializations compared to vi. "vs" used to make cursor very visible,
	or for scrollbars (Webb)?
MSDOS: After writing on a network the 'w' bit for others is set.
When can the 'p' and 'P' command not be redone??


Problems that will probably not be solved:

Prolem with HPterm under X (cosentino/2).
Amiga: When using quickfix with the Manx compiler we only get the first 25
	errors. How do we get the rest?
Amiga: The ":cq" command does not always abort the Manx compiler. Why?
Linux: A file with protection r--rw-rw- is seen readonly for others. The access()
	function in GNU libc is probably wrong.


Further extentions and improvements:

Add icon setting for xterm (riehm/69, mulder/iconname.set).
Make command line arguments options to be combined after a single dash, eg "-nb".
When started to edit another file, make message "file 1 of 8" different.
When entering text, keep other windows on same buffer updated (when a line
	entered)?
Amiga: When 'r' protection bit is not set, file can still be opened
	but gives read errors. Check protection before opening.
Bind windows together, scrolling is done in both windows synchronous
	(horizontally and vertically). Use CTRL-W b?
Re-select last Visual selection with "v." (exactly same text, from '[ to ']).
Don't write any pages into the swapfile until the buffer has been changed.
Catch terminating signals and call ml_sync_all(): SIGHUP, SIGINT, SIGQUIT,
	SIGILL, SIGABRT, SIGFPE, SIGPIPE, SIGALRM, SIGTERM, SIGBUS, SIGSEGV.
Change ".swp" to ".vim", because it give a hint who created the file?
Use termcap 'ts' and 'fs' entries for setting the window title. Check 'hs'
	and use minimum of 'ws' (if present) and Columns to truncate the title.
When writing check for file exists but no permission, "Permission denied".
In dosub() regexec is called twice for the same line. Try to avoid this.
When line is too long to fit on screen, don't display it.
When inserting makes cursor go past end of screen, scroll up in insertchar().
Window updating from memline.c: insert/delete/replace line.
Optimize ml_append() for speed, esp. for reading a file.
V..c should keep indent when 'ai' is set, just like <count>cc.
In visual select mode: Inclusion or exclusion of char under cursor depends
	on movement command. "vwd" and "dw" do the same???
Find out why macros of Stephen Riehm are working strange.
:s///p prints the line after a substitution.
Make CTRL-R (insert register contents) also work in command line mode.
Updatescript() can be done faster with a string instead of a char.
Add arguments to ":args", like ":next".
When searching with 'n' give message when getting back where the search first
	started. Remember start of search in '/ mark.
Add option that scrolls screen to put cursor in middle of screen after search.
Add \! to search patterns: matches string that does not match previous atom.
Screen updating is inefficient with CTRL-F and CTRL-B when there are long lines.
Use 'backupdir' for all backup files if it starts with '>'.
When writing a file, name it "foo.new". Then rename "foo" to "foo.bak" and
	"foo.new" to "foo". If dir is not writable or on write error copy "foo"
	to "backupdir/foo.bak" and overwrite "foo". Check for correct group/owner
	and try to set it if not. NO: this breaks with hard links.
	INSTEAD: make Amiga and MSDOS work like unix: first make copy of file, then
	truncate and overwrite original file. Use an option for this, default
	on for Unix, off for Amiga/MSDOS.
Use CTRL-E and CTRL-Y in insert mode for scroll up/down?
Uppercase characters in ex commands can be made lowercase?
Add t_del, code for delete key (termcap 'kD') and maybe some other keys:
	'kI' insert key, 'kL' delete line, t_bs 'bs', etc.
Filtering a block should only apply to the block, not to the whole lines. When
	the number of lines is increased, add lines. When decreased, padd with
	spaces or delete?
CTRL-V > should move the block, not whole lines.
Add commands to move selected text, without deselecting.
Add "p" command to swap selected text with unnamed buffer.
Add "P" command to insert contents of unnamed buffer, move selected text to
	position of previous deleted (to swap foo and bar in " + foo")
In out-of-memory situations: Free allocated space in undo (after asking).
8-bit codes between 0x80 and 0xa0 cannot be typed directly (mostly msdos
	problem). Need more codes for delete key and more function keys. Use
	2-byte code? (see xvim).
Insert octal numbers with CTRL-V o, hexadecimal with CTRL-V x and binary
	with CTRL-V b.
List mappings: Once with and without ^ and ~ (meta keys). Use "F1" and "PgUp"
	for MSDOS default mappings.
Add option that tells which characters to display directly, e.g.
	":set gr=32-126,140-244", others are displayed with ^ and ~ and +
Add option to show character value in octal, decimal, hex and screen code.
How does vi detect whether a filter has messed up the screen? Check source.
	After ":w !command" a wait_return?
Improve screen updating code for doput() (use s_ins()).
With 'p' command on last line: scroll screen up (also for terminals without
	insert line command).
Amiga: ExpandWildCards in amiga.c: don't expand if there are no wildcards.
unix: Speedup wildcard expansion of "*", "~" and "$": do it internally, more
	complicated things can still be done with the shell.
Only do wildcard expansion with 'wildchar' when entering a command that has a
	file name as argument (:r :w :! :e :f :n)?
Unix: When comparing two file names to see if they are the same file use stat()
	and compare device/inode; much faster than FullPathName()
In regexp.c: "\^" after "\|" or "\(" is start of line, and "\$" before "\|"
	and "\)" is end of line.
Remember the "last changed" time of the edited file and check it before
	overwriting; another user may have changed it.
Support for command lines longer than 256 characters (for EXINIT).
Option for filter when reading/writing a file for compression or crypting.
Option to set time for emsg() sleep. Interrupt sleep when key is typed? sleep
	before second message?
Delete message after new command has been entered and have waited for key.
Add "next tag" command for tags that have multiple hits.
Support static tags: first search for tags with current filename: "foo.c:bar",
	then for global tags (without a filename).
History stack for . command?
Use insert/delete char when terminal supports it.
With undo with simple line delete/insert: optimize screen updating.
Optimize screen redraw for slow terminals.
"edit" option: when off changing the buffer is not possible.
Add "-d null" for editing from a script file without displaying.
Add "-R" for readonly mode (ex has it).
When writing to a readonly file, ask for permission to overwrite it (if file can
	be made writable) and restore file to readonly afterwards.
MSDOS: search for _exrc in the directory where the binary is, instead
	of using $VIM\_exrc.
In insert mode: Remember the characters that were removed with backspace and
	re-insert them one at a time with <key1>, all together with <key2>.
Amiga: Add possibility to set a keymap. The code in amiga.c does not work yet.
Implement 'redraw' option.
Add possibility to put the value of an option into the text: "'lines'p
Unix: WildExpand: Without csh file name with embedded space will be split in two.
With wildcard expansion after '%' and '#', expand current/alternate file name, so
	it can be edited.
Add special code to 'sections' option to define something else but '{' or '}'
	as the start of a section (e.g. one shiftwidth to the right).
Nopaste option: Mappings with non-printable characters are OK.
Add 'indent' option: Always use this amount of indent when starting a new line
	and when formatting text.
Add 'crown' option to 'Q' command: preserve indent of second line.
When formatting with 'Q', break at paragraph boundaries (empty lines).
When 'textwidth' is negative, use for 'Q' only, no automatic formatting.
Add option 'comment', initally "/*,*,*/,#", giving the characters at start of
	a line that should be left alone by the internal formatting.
After formatting with Q the cursor is on the end of the last line; with = and
	when formatprg is set it is at the start of the first line. Not good.
Add 'scrolloff': scroll when cursor is less then 'scrolloff' lines from top/bottom.
Add option to switch off ignoring braces inside quotes for "%" command??
Use pipes for filtering on unix.
Allow for +command and -option on any position in argv[].
Add commands like ]] and [[ that do not include the line jumped to.
When :unab without matching "from" part and several matching "to" parts,
	delete the entry that was used last, instead of the first in the list.
After :set nowrap remove superflous redraw with wrong hor. offset if cursor
	is right of the screen.
Add -x option: crypt/decrypt when writing/reading file.
Add count to ':', gives ":.,.+count-1"
Improve online help: Fit into the window (also small ones), hypertext, etc.
	(See also dh1:text/vi/vi.help). View help just like a file?
Support several errorformats, use the first format that matches.
Recognize "$*" in 'makeprg'; replace it by the arguments to :make.
Allow multiple arguments to :unmap.
Add option that contains characters which are included in identifiers;
	default "[a-bA-B0-9]_", for LISP "[a-bA-B0-9]_-".
With :s///c highlight the pattern to be replaced and replace \&, ~, etc. when
	showing the replacement pattern.
Add mappings for visual mode; use marks for start/end of selected text.
With ambigious mapping, print conflicting entry.
In insert mode add # for CTRL-R  (alternate filename).
Highlight search string when found?
Command line: cursor up on empty line: go to previous command, on non-empty line:
	go to previous matching command.
Add command to clear all mappings, "clearmap".
Add text justification option.
When the edited file is a symlink, try to put the .swp file in the same dir as
	the actual file. Adjust FullName().
Add new operator: clear, make area white (replace with spaces)
Add put function that replaces the text under it.
After "inv"ing an option show the value: ":set invpaste" gives "paste is off".
After ":read" set '[ and '] marks.
In fileio.c replace filemess() by outputting strings after each other (only
	one wait_return().
After executing a shell, put tty back in raw mode (for shells that mess with
	the tty settings)
Make program to transform termcap entries into something that fits in tcarr
	structure.
Improve error messages: when expanding '%': "no filename to substitute for '%'"
	when expanding '#': "no alternate filename to substitute for '#'"
Put warnings in some color (errors are inverted, normal messages plain).
Check handling of CTRL-V and '\' for ":" commands that do not have TRLBAR.
When a file cannot be opened but does exist, give error message.
If file does not exists, check if directory exists.
MSDOS: t_cv and t_ci not set, but do invert char under cursor.
Add option to switch off move to start of line (Waggoner/12 and 13).
Command to show keys that are not used and available for mapping.
Settings edit mode: make file with ":set opt=xx", edit it, parse it as ex commands.
When memory gets low, reduce the number of undo levels (with confirmation).
Add 'para_regex' option: regular expression for end of paragraph.
tag-completion command: when tag found, replace it by the prototype, when not
	found, replace it by the longest match.
make listings in a more-like way (mappings, files, settings, etc.).
":set -w all": list one option per line.
Before overwriting a non-writable file with ":w!" ask for permission.
Amiga: test for 'w' flag when reading a file.
When appending to the last line, causing it to wrap, screen redraw first does it
	at a wrong position.
Include patches for Russian text (Marinichev/4).
Ex commands in a mapping should not be put in the command line history.
Option not to change the search string when using a :tag command.
Error message for ambiguous mapping: Include the arguments.
Add ":retab". When "et" set, convert tabs to spaces, when "noet" vice versa.
	":retab 8" will replace tabs and spaces with the current "ts" setting
	to a "ts" of 8.
:table command (Webb)
Add command to go to last non-blank in line (like 0 vs. ^, $ vs. ???)
Add 'backupdiralways', 'bda' option for 'bdir', like 'da' for 'dir'.
Add option to recognize identifiers with everything but spaces ('forth'?).
	Adjust isidchar().
MSDOS: How about supporting function keys #11 and #12?
With blockwise visual mode and "c" command, insert same text in every line.
Search filenames for starting with $HOME and replace it with "~" when displaying.
For 'shell' option add possibility to give arguments for fast start (e.g. -f).
	Not to be used for ":shell".
Make ":e file1 file2" work like ":n file1 file2"?
Give message "No lines in buffer" when last line in buffer deleted.
When displaying (file xx of yy), add "not" when curbuf is not file xx.
Add commands to do things in all buffers: ":Substitute", ":searchall", etc.
Make ":sleep" accept floating point numbers, like ":sleep 0.01".
When in replace mode and 'expandtab' set, make tab look like spaces.
Support multiple search buffers, so macros can be made without side effects.
With :read set '[ and '] to start/end of new lines
Make builtin termcaps with a configuration file and a program to translate
	it into a .h file.
Use %> and #> for filename without path?
Allow multiple arguments for ":edit", add them to the argument list.
Allow multiple arguments for ":read", read all the files.
Make options from modelines only used in the buffer where the file is read.
For visual mode: "." does a search for the string in the marked area. Only
	when less than two lines. What key to use for backward search?
Matching with "%" should be configurable. 'matchstrings' =
		(/*,*/),(^#if,^#else,^#endif)
Expanding ~ and $VAR in options should be done not only for the first entry.
Add 'resizecmd' option: vi command to be executed when window is resized.
Do not accept mappings when waiting for key hit with --more--.
Add option to make settings from modelines valid only in the file where they
	were set. Reset options when starting to edit another file.
Keep output from listings in a window, so you can have a look at it while
	working in another window. Put cmdline in a separate window?
Keyword completion code should use the case from the match.
Add regular expression \{m,n\}: m to n matches. \{m\} is m matches, \{m,\} is
	at least m matches. Also do \{,n\}: up to n matches.
When 'backup' is not set and 'writebackup is set, use a unique name for the
	backup file, don't deleted the ".bak" file.

From Elvis:
fontchanges recognized "\\fB" etc.
:color command
:if and friends, conditional statements
Read .exfilerc when starting to edit a new file (can be used to load macros for
	specific file type).
Change cursor shape in command/insert mode.
'flipcase' variable: upper/lower case pairs.

From nvi:
'cdpath' option.
'remapmax' option.
Allow editing lines that do not fit in the window.

From xvim:
Use '\' before commands to make them linewise.
Allow a newline in search patterns (also for :s, can delete newline).
	Add BOW, EOW, NEWL, NLORANY, NLBUTANY, magic 'n' and 'r', etc.
Add register for ':', '?' and '/' commands? (yank_buf()).
Support mouse control (also weissman/1). With option to switch it off to
	enable copy/paste.
Searching in help file.
get code for backspace from termcap.
Remember last cursor position, optimize setcursor().

From xvi:
CTRL-_ : swap 8th bit of character

From vile:
CTRL-X e: edit file name under the cursor (like ^] and *)
Show unprintable characters in hex.
Use scrollbar.
When horizontal scrolling, use '<' and '>' for lines continuing outside of window.

Far future extentions:

Allow vertical splitting of screen (once).
Allow editing beyond end of line, just like there are all spaces. Switch this
	on with an option or special insert mode command. Also allow editing
	above start and below end of buffer.
MSdos: use extended or expanded memory.
When executing macro's: Save each line for undo only once.
Smart cut/paste: recognize words and adjust spaces before/after them.
Add 'notwsuffixes' option: suffixes for files where 'tw' should be 0.
Make files with suffix in 'suffixes' option always appear in list of matched
	files, but at the end.
Keyword completion: first look in the file for a match, then in a dictionary (Webb).
Option verbose; when on keep the screen uptodate, when off only redisplay when
	input needed.
Change the output to the message line. Don't redraw the screen until the next
	vi command. Remember message line for redraw. Integrate the command line
	in updateScreen().
Mode to keep text formatted while inserting/deleting. Use soft/hard returns with
	an option to switch this off.
Mode to keep C-code formatted (sort of on-line indent). Use colors for
	keywords, comments, etc.
Korn-shell like command line editing (like editing a single line with vi). Use
	:cmap! for mappings. Can be implemented like a buffer containing command
	lines.
Add column numbers to ":" commands (:line1:col1,line2:col2 cmd). Block can be
	selected with CTRL-V.
Add 'hidecomment' option: don't display comments in /* */ and after //.
Add open mode, use it when terminal has no cursor positioning.
Add macro language with real functions.
File in local directory to store contents of named registers and named marks.
	Write when quitting, read when starting.
Special "drawing mode": a line is drawn where the cursor is moved to. Backspace
	deletes along the line (from jvim).
Save cursor position (and other things) for a next editing session.
Perform commands on multiple windows (:W%s/foo/bar/g), multiple arguments (:A)
	or multiple buffers (:B).