Using the script from http://wiki.beryl-project.org/index.php/Install/Ubuntu/Edgy/XGL#Adding_an_Xgl_login_session , under "Shutdown and reboot buttons in GNOME" fixes the issue for me.
Using the script from http:// wiki.beryl- project. org/index. php/Install/ Ubuntu/ Edgy/XGL# Adding_ an_Xgl_ login_session , under "Shutdown and reboot buttons in GNOME" fixes the issue for me.