Comment 2 for bug 1307201

This problem does not seem to be limited to GParted. It also occurs for GNOME-Control-Center, and Banshee.

See:
GLib-CRITICAL **: Source ID was not found when attempting to remove it - warning when leaving Network menu of g-c-c
https://bugs.launchpad.net/ubuntu/+source/gnome-control-center/+bug/1264368?comments=all