Here is the related bug in GParted:
https://bugzilla.gnome.org/show_bug.cgi?id=729800
https://bugzilla.gnome.org/show_bug.cgi?id=729800#c12 explains the problem
well:
This is the extra checking added to Glib which generates the critical error:
https://git.gnome.org/browse/glib/commit/?id=a919be3d39150328874ff647fb2c2be7af3df996
gmain: Warn when g_source_remove() fails
In the end, the bug basically is harmless (it indicates an attempt to free
memory that has already been freed). It was corrected in the later versions
of GParted.
