Qt::WA_PaintOnScreen does not switch on Qt::WA_NativeWindow

Our documentation states that Qt::WA_PaintOnScreen will also enable Qt::WA_NativeWindow. This is written out under "Native Widgets vs Alien Widgets" here: http://qt-project.org/doc/qt-5/qwidget.html

However, this does not actually seem to happen automatically. I have to separately enable Qt::WA_NativeWindow.

In my case I have also reimplemented QWidget::paintEngine to return Q_NULLPTR as I needed native (DirectX) painting - I am not certain whether that should affect these widget attributes. Without Qt::WA_NativeWindow enabled explicitly in addition to Qt::WA_PaintOnScreen the widget always displays as all black.

My understanding is that for native painting enabling Qt::WA_PaintOnScreen and returning Q_NULLPTR from QWidget::paintEngine should be enough.