Origin: backport, commit:0c907ab8222859a645d9a2549da7d18ef11f8326
Author: Marc Sabatella <marc@outsideshore.com>
Description: fix #309333: crash hiding palettes
 Resolves: https://musescore.org/en/node/309333
 .
 Crash happens on trying to set the focus upon closing the palette,
 we try to restore the previous focused widget.
 But it may no longer be valid.
 .
 Changed to return focus to the score view if possible,
 otherwise let Qt worry about it.

--- a/mscore/musescore.cpp
+++ b/mscore/musescore.cpp
@@ -5791,17 +5791,14 @@ void MuseScore::cmd(QAction* a)
             PaletteBox* pb = mscore->getPaletteBox();
             QLineEdit* sb = pb->searchBox();
             if (a->isChecked()) {
-                  lastFocusWidget = QApplication::focusWidget();
                   sb->setFocus();
                   if (pb->noSelection())
                         pb->setKeyboardNavigation(false);
                   else
                         pb->setKeyboardNavigation(true);
                   }
-            else {
-                  if (lastFocusWidget)
-                        lastFocusWidget->setFocus();
-                  }
+            else if (cv)
+                  cv->setFocus();
             return;
             }
       if (cmdn == "palette-search") {
--- a/mscore/musescore.h
+++ b/mscore/musescore.h
@@ -349,7 +349,6 @@ class MuseScore : public QMainWindow, pu
       PaletteBox* paletteBox         { 0 };
       Inspector* _inspector          { 0 };
       OmrPanel* omrPanel             { 0 };
-      QWidget* lastFocusWidget       { 0 };
 
       QPushButton* showMidiImportButton {0};