Comment 18 for bug 491940

I've uploaded a patched gnome-session package in the Greek schools ppa. Now the clients properly reboot/shutdown from gnome-panel or from iTalc.

Anyone interested may other add the ppa to his sources and update by doing
  `sudo add-apt-repository ppa:ts.sch.gr && sudo apt-get update && sudo apt-get dist-upgrade`
or he can manually download the .deb from
  https://launchpad.net/~ts.sch.gr/+archive/ppa/+sourcepub/1134508/+listing-archive-extra

I tried to press the shutdown button on a thin client to test if the session menu would also work, but that button event never reaches the server, so I didn't even see the session menu (dbus events from the thin clients system bus do not propagate to the server). So the patched package works in all reproducible cases for me.