Regression: Dock widget overlaps resized menu widget

If the height of the menu bar is changed by adjusting the minimum height of the menuWidget then the dock widgets set for the main window will overlap the menu bar.

With custom menu widget this was working correctly in Qt 4.7.4. Resizing the default menu bar however newer worked.

Attached example can be used to reproduce both cases (default and custom menu). The pictures also show the overlapping dock widget.