With a QGLWidget inside a QTabWidget the mouse and enter/leave events are not working correctly

With a QGLWidget inside a QTabWidget the mouse and enter/leave events are not working correctly. In the attached example, there are two tabs, both with a QGLWidget set on each. In the first tab, no leave event seems to occur and nor does it get any mouse events either. When clicking on the second tab, the leave events work if you go into the tabbar (the background is grey then) but not if you go outside of the QGLWidget on the sides.

This appears to be a Mac specific problem.