Unity steals focus, even if input has been grabbed

[covox]

There are several applications which use XGrabKeyboard to ensure the full range of keypresses can be used by an application. A good example is in DOSBox; quite a lot of games use the <Alt> key to jump, so you can turn on input-grabbing to prevent the window manager from acting on keypresses (e.g. <Alt>+<Right> to switch desktops).

Of course <Alt> is now intercepted by Unity's HUD feature, and this interception somehow overrides XGrabKeyboard.

Ways to reproduce:
- Open up DOSBox
- Press <Ctrl> + <F10> to grab the keyboard and mouse input
- Press <Alt>, Unity HUD will take over and DOSBox will lose focus

[covox (covox)]

I don't think that this bug is an exact duplicate of https://bugs.launchpad.net/bugs/806255, as that one is filed against Compiz. While it probably shares the same type of incompatibility between XkbStateNotify and XGrabKeyboard, the location of this one would be in Unity 2D.

[Gatis Paeglis (gatis-paeglis)]

This affects Qt applications as well. Reproducible with plain xcb code, see the code in the attachment.

[Gatis Paeglis (gatis-paeglis)]

test code