Set Qt::AA_DontCreateNativeWidgetSiblings to true and make some widgets to native window, when the window size changed ( showMaximized/showNormal e.g.), the native window not redraw correctly. But when resize by draging the window edge, the problem gone.

On Linux, the problem exists on first shown.

Build the demo from attachment with lastest Qt, run and maximized you will see the bug.

It seems that the widget position not sync correctly with it's native window cause the problem.