When top level widget contains pop up menu and clicking the widget we can see that mouse click event is passed to underlaying widget which comes to top level. Test with attached example:

• drag child widget on top of main widget
• click right mouse button to launch menu
• click left button on top of child widget
• Mainwindow comes to top level widget and changes the color (mouse event test)
• Expected is that child widget stays on top and pop up menu is closed

This is regression from Qt 5.2.1

Change that cause the issue:
https://codereview.qt-project.org/#change,82461