window: Don't mark the event as handled for odd event combinations

This is an accidental regression from 7a109a1. If we mark the event as
handled, then we *need* to set grab_op, or do some other sort of
behavior, since we have a grab.

src/core/window.c

@@ -8022,7 +8022,7 @@ meta_window_handle_ungrabbed_event (MetaWindow         *window,
       return TRUE;
     }
 
-  return TRUE;
+  return FALSE;
 }
 
 void