Navigator toolbar empty/blank in Kontact
I use Kontact for e-mail/calendar/etc. I turned on the 'Navigator' toolbar, so I could get rid of the navigation bar on the left-hand side (taking up too much screen real estate). Well, it was fine at first, but then I somehow messed it up, and now the toolbar is empty, and I can't add anything back to it.
How can I reset the toolbar back to its default?
I'm still fairly new to Linux, so go easy on me, please. :-)