I've always liked the idea of adding and re-arranging gadgets in both the left and right hand panes in the CMS editing UI, but there is something bugging me:

Why can you remove the Content Tree gadget (the one containing Pages, Sites, Tasks and Project Items) - but there is no way to add it back using the "Add gadgets" dialog? 
(Yes, I know you can restore it by using "Reset Views" under my profile, but that resets all gadget settings.)

The Content Tree (or at least, Pages) gadget is the most central one of all, and should either be
A) moveable, but not removeable,
or B) possible to easily add back in the "Add gadgets" dialog.

What am I missing?