Pop up menus disappear on repaint events

[GimpMaster]

Yeah i'm just using the default main() function that Visual Studio created.

QApplication a(argc, argv);
	MainWidget w;
	w.show();
	return a.exec();

QApplication a(argc, argv);
	MainWidget w;
	w.show();
	return a.exec();

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Is there a problem with doing that? The other thing is I'm using 4.6.0 Qt, so maybe this has already been fixed?