I'm running Xubuntu 14.04 and when I try to shut down or restart via the GUI, it just goes to the login screen. I know a lot of people seem to have a similar problem, but usually they can shut down once they reach the login screen. I cannot, instead all the options to shutdown, sleep, etc. are grayed out. Shutting down and restarting via the command line works fine.

I've tried to edit my xinitrc file by adding the line ck-launch-session startxfce4
which seems to be a fix for some people, but no luck...