On Mac, when calling showFullScreen() moving the cursor to the top of the screen causes the menu / toolbar to show always, there is no easy way to implement a kiosk like application because of this.

It would be nice if QWidget::showFullScreen() was overloaded with
QWidget::showFullScreen(bool hideMenuBarForever) (or with a better
name for the argument) so that Qt developers have the choice if they
want the menu bar never to reappear.