Toplevel QOpenGLWidget without children freezes until device is rotated

A toplevel QOpenGLWidget will receive a resize event to 0x0. This makes the widget believe it is hidden, and it will not get any paintGL() calls.

Rotating the device will generate a resize event.

The workaround is to use QOpenGLWindow instead, which is a much better alternative in 99.9% of the cases.