shutdown dialog immediately closes, restarts system

[Josh Stratton]

I've been experiencing a bug as shown below, where the shutdown dialog
will immediately pop closed and the system will restart about 20% of
the time.  While it's only annoying, I'd like to somehow debug what's
going on.  Is there a debug log or something that could help me
resolve this?  I could find anything relevant in the kernel or X logs.

https://bugs.launchpad.net/ubuntu/+source/gnome-session/+bug/1170783