Comment 26 for bug 495121

I'm getting it too. It wouldn't be so bad if I could restart it. Although compiz --replace does restart compiz I lose the gnome title and footer tiles so it's no use. I end up having to do a 'metacity --replace' so I don't have to shutdown all apps, reboot and start them all again.

Using Preferences/Visual Effects doesn't work either - just behaves the same way as compiz --replace.

It seems to have increased in frequency over the last couple of months.