Comment 9 for bug 934062

Confirmed. This seems to happen a lot. It's very intrusive.

I haven't looked yet, but if Unity still handles key events directly while Super is held then it should be easy to fix in Unity. Otherwise, the relevant functionality is already implemented in compiz (to detect secondary keystrokes while a modifier is held) and we possibly just need to expose that info to plugins like unityshell in a new way, _before_ the Terminate callback is triggered.