link undo in main window to editor if the latter has focus (bug #44402) * file-editor.cc (editor_tab_has_focus): helper function checking whether an edit area has the focus; (copyClipboard, pasteClipboard, selectAll): use this helper function; (do_undo): new slot for the undo action triggered from the main window * file-editor.h: new helper function and new slots * main-window.cc (handle_undo_request): emit a signal for undo instead of undoing in terminal window when terminal does not have focus * main-window.h: new undo signal * octave-dock-widget.cc (octave_dock_widget): connect undo signal from main-window to new virtual slot; * octave-dock-widget.h: new virtual slot do_undo, doing nothing

--- a/libgui/src/octave-dock-widget.h	Sat Mar 14 14:52:58 2015 +0000
+++ b/libgui/src/octave-dock-widget.h	Sat Mar 14 18:54:23 2015 +0100
@@ -97,15 +97,11 @@
       emit active_changed (true);
   }
   /** slots to handle copy & paste */
-  virtual void copyClipboard ()
-  {
-  }
-  virtual void pasteClipboard ()
-  {
-  }
-  virtual void selectAll ()
-  {
-  }
+  virtual void copyClipboard () {  }
+  virtual void pasteClipboard () {  }
+  virtual void selectAll () {  }
+  /** slots to handle undo */
+  virtual void do_undo () {  }
 
   // event filter for double clicks into the window decoration elements
   bool eventFilter(QObject *obj, QEvent *e);