+ virtual bool IsActive() { return wxGetTopLevelParent(FindFocus()) == this; }
+
+ // this function may be overridden to return false to allow closing the
+ // application even when this top level window is still open
+ //
+ // notice that the window is still closed prior to the application exit and
+ // so it can still veto it even if it returns false from here
+ virtual bool ShouldPreventAppExit() const { return true; }
+