Fix undo after breaking a nested paragraph

We have to take into account that Buffer::updateBuffer can modify the document.

Fix bug #11292.

(cherry picked from commit 57feb0fed0)

src/frontends/qt4/GuiApplication.cpp

@@ -1403,11 +1403,13 @@ DispatchResult const & GuiApplication::dispatch(FuncRequest const & cmd)
 		// This handles undo groups automagically
 		UndoGroupHelper ugh(buffer);
 		dispatch(cmd, dr);
+		// redraw the screen at the end (first of the two drawing steps).
+		// This is done unless explicitly requested otherwise.
+		// This code is kept inside the undo group because updateBuffer
+		// can create undo actions (see #11292)
+		updateCurrentView(cmd, dr);
 	}
 
-	// redraw the screen at the end (first of the two drawing steps).
-	// This is done unless explicitly requested otherwise
-	updateCurrentView(cmd, dr);
 	d->dispatch_result_ = dr;
 	return d->dispatch_result_;
 }

status.23x

@@ -65,6 +65,9 @@ What's new
 
 - Fix broken space dialog in mathed (bug 7747).
 
+- Fix undo in some cases involving nesting (bug 11292).
+
+
 * INTERNALS