Speaking of g-c-c...
I just stepped through all of the options, in the User Menu.
They all worked, except "Settings -> Hardware -> Power".
g-c-c exits, with no error dialog , when I click the "Power" icon.
EDIT
Error dialog...
Code:
(gnome-control-center:5442): GLib-GIO-ERROR **: Settings schema 'org.gnome.settings-daemon.plugins.power' does not contain a key named 'lid-close-ac-action'
Trace/breakpoint trap