In Qt4 one could create a widget with attributes WA_StaticContents and disable the autofillbackground so that:

• widget contents would never be cleared on update/resize
• paint events after a resize would refer to the new regions of the widget (if it grew)

In Qt5 however I am unable to get this to work. I've attached an example that fills the widget red on the first resize event.

Expected behaviour: In Qt4 the original red fill is always visible, resizing the widget to a larger size, displays excess margins in a different color, and the paintEvent region matches those margins.

However: In Qt5 the red fill disappears as soon as you resize the widget again. The paintEvent region following the resize is the entire widget.