Fix wrong return value in the changes of r73365.

Really fix menus under Unity.

Closes #14961.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73368 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/menu.cpp

@@ -62,7 +62,8 @@ static bool IsMenuEventAllowed(wxMenu* menu)
         wxWindow* tlw = wxGetTopLevelParent(menu->GetWindow());
         if ( !tlw || !wxDynamicCast(tlw, wxDialog) )
         {
-            return true;
+            // This must be an event from a menu bar of one of the frames.
+            return false;
         }
     }