Modal dialog with QWinWidget parent and WA_DeleteOnClose attribute is deleted when application window is hidden

Show a modal dialog which has a QWinWidget instance as a parent and which has the widget attribute WA_DeleteOnClose set.
Hiding the MFC application window, which is the parent of the QWinWidget instance, will delete the dialog!

 case QEvent::Hide:
	...
        if (w->testAttribute(Qt::WA_DeleteOnClose) && w->isWindow())
 	    deleteLater();
	break;

I expect the dialog to be hidden and reappear when the application window is shown again; certainly not deleted.

see http://stackoverflow.com/questions/1482010/minimizing-mfc-application-with-open-qt-dialog as well