Closing GNOME session no longer ask for confirmation

[Mariano Draghi]

Hi,

Somehow the "exit" button no longer asks for confirmation, and
closes the session immediately. 

I don't know exactly how or when this stopped working. I've been
installing/uninstalling/tweaking a few things, but nothing session
related (at least nothing of what I'm aware of...)

Is there any setting to enable/disable this confirmation? How can I
restore it?

Thanks!

-- 
Mariano