Recovering Thunderbird's folder pane

Ah, um, er, uh, I accidentally clicked somewhere I shouldn't have and 
the folder pane disappeared. Took me a while to discover/recall that 
clicking near the edge of the Quickfilter reopened the folder pane.

IMO, folder pane open/closed should be in Menubar --> View (maybe --> 
Layout).

And the Qickfilter toolbar should be toggled in View --> Toolbars. I'm 
sure it's useful to a lot of people, and just extra clutter for a lot of 
others (like me.)

Wolf K.