I had the same bug with the logout dialog also... Could someone provide a .xsession-errors from a session that didn't restart/shutdown correctly (if you relogged in after, it will be in .xsession-errors.old instead)? If you can see some errors such as "error 104 (connection reset)", I think Xorg is crashing on shutdown (this bug only appeared with the recent X upload).
I had the same bug with the logout dialog also... Could someone provide a .xsession-errors from a session that didn't restart/shutdown correctly (if you relogged in after, it will be in .xsession- errors. old instead)? If you can see some errors such as "error 104 (connection reset)", I think Xorg is crashing on shutdown (this bug only appeared with the recent X upload).