Clicking contextual menu item is not always triggered; contextual menu sometimes hangs

Clicking a contextual menu item does not always get triggered. I've noticed this in my own application and in the Qt Creator version that's shipped with Qt 5.2 beta as well.

Bonus bug: Sometimes the contextual menu will "hang" when selecting an item, staying visible, and the only way to get rid of it is to quit the application. Again, in my own application and Qt Creator.