Crash when moving a window containing a widget with zero size and a widget where winId() had been called to another screen.

Qt crashes with the following message: ASSERT: "!rect.isEmpty()" in file kernel\qwidgetbackingstore.cpp, line 582

To provoke this, the following conditions must be met:

• A multi-monitor setup
• The window needs to contain a widget with zero height or width
• The window needs to contain a widget where winId() has been called (i.e. where a native window has been created)
• The user has to move the window completely to the secondary screen.

I personally observed this in VirtualBox, a minimal sample program is attached.