QGLView can't be used on container widgets anymore

Because QGLView inherits QWindow now (and not QGLWidget as it does before) it can't be used on QDockWidget, QTabWidget, QStackedWidget or any other container widget anymore. (QDockWidget::setWidget() expects a QWidget as parameter). So one possible solution might be to give the container classes overloaded methods to accept QWindow derived classes, e.g.
QDockWidget::setWidget/setWindow(QWindow * window);
QTabWidget::addTab(QWindow * page, const QString & label);
etc.

That might be the same problem as described in
https://bugreports.qt-project.org/browse/QTBUG-25643
but QGLView isn't explicitly mentioned there.