Open one window on a workspace. Press Alt-Tab. This leads to a frozen system, mouse clicks don't work any more. Alt-Tab again solves the problem.
I'm not seeing that here, can you update to rev. 22776 and report?
Can you update to rev. 22803 and try again?
Seems to be fixed. Thanks.
*** Bug 2170 has been marked as a duplicate of this bug. ***