Comment 29 for bug 812394

Yes, please provide an easy to find method to switch it on. It took me some googling to find how
to enable it, and it was not obvious at all, that it was intentionally disabled. It looked like a bug
(on xfce, a window pops up: not authorized)

And although I count myself as reasonably computer literate, I know next to nothing about policykit et al,
and would never thought by myself to edit /var/lib/polkit-1/localauthority/10-vendor.d/com.ubuntu.desktop.pkla