I've noticed a workaround. Pressing Alt-Tab a few times seems to cure it, which is quite a relief.
By the way, I'm using focus-follows-pointer (System->Preferences->Windows, Select windows when the mouse moves over them). I'm wondering if everyone who experiences this bug has focus- follows-pointer. -- No more mouse events https://launchpad.net/bugs/55739 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs