Under windws, if a QApplication have set setQuitOnLastWindowClosed to false,
and there is no window left (a tray app for exemple):

Qapplication doesn't catch the WM_CLOSE event sent when:

• taskkill command
• QtCreator "stop" button
• Windows end session (logout, shutdown, etc...)

It's may be caused by hwnd == 0 not managed in Qt

You can see the bug and a work-around in attached file