Bug#427406: metacity: No more mouse/keyboard-input possible, after closing crashed application

[manphiz]

Thanks to curiosity, I updated my metacity from 1:2.14.5-4(testing) to 
current unstable 1:2.18.5-1, and when encountering "Force Quit" 
situation, everything works fine at my place: no lockup, no 
non-responding, everything is fine.

Maybe you were still staying at 2.18.3? Try the newer version. Or maybe 
something else is culpable on your particular system?