Same problem here. I use ATI card and run xgl & compiz from ~/.Xsession file, running after gdm is loaded. I can only logout, switch user, lock screen and hibernate from gnome when running xgl, but not shutdown or restart.
-- Incomplete logout options with XGL https://launchpad.net/bugs/36321 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
