I've heard about this happening on vanilla wine as well.
When I finish playing WoW: I log out of my current character, hit the "Back" button and then hit "Quit".
The "Quit" button sinks in but never pops back up and the game screen stays on the screen and music and sfx still plays. I end up having to do a 'pkill wine' and then an init 3/init 5 to get back into X.
I'm currently not running it in an emulated desktop, I usually do as I am running a dual monitor setup, then I'd normally use xkill on the window.
Anybody else having the freeze on quit problem?