Comment 44 for bug 486154

Yes, I had the same behavior with "killall metacity" (which I was using because I was recompiling it with various things commented out). I'll run some compiz tests and make sure I can reproduce your results. I think there -is- some negotiation going on, and I'm not sure what happens if a process asks X to hand it events and then dies or is killed; do the events get black-holed? I'll pull down the sources to those compiz processes if I can find it and take a look as well, though it'll be a superficial look. More in a bit.
(Might also be interesting, after switching to compiz and back, to kill the left-behind compiz processes and see if that changes anything.)

Together we'll kill this thing.

[Possibly even with fire. That comment of yours early on had me in stitches.]