I like the org-agenda-set-restriction-lock feature,
but I recently wasted quite a bit of time troubleshooting my agenda
views, only to find out that I'd set the restriction lock to
a single file.

Is there an option to toggle that would show me that I have
the agenda restricted to a single file?  The only visible notifier that
I found was on the "Agenda->Agenda Files" menu, where it said "Restricted to

a single File".

Thanks,
--Nate