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.