Missing folders pane in Firefox Thunderbird?

[Ernest]

My folders pane in Thunderbird has disappeared. This keeps me from
going to folders other than the inbox, like the "sent" messages and
the "drafts" folders, which is of course a real pain. I have looked
at length and cannot find any info on restoring the folders
pane/window that used to be at the left of the Thunderbird program.
Any help would be appreciated.

[Owen]

The simplest thing that comes to mind is that the pane has been shrunk
to zero. At the left hand edge of the TB window will be a vertical
border. Click and drag to the right to expand the pane. If that's not
it then something's broken.

[Ernest]

I never would have guessed from looking at it,
but dragging it back out worked perfectly. I do not recall dragging
it shut, but I see that if you drag it to a certain point, it then
jumps the rest of the way to disappear. That must have happened when
I wasn't really paying attention. Deepest thanks for your help, and
for being a supporter of Mozilla!

[Owen]

My pleasure. I just love it when it's the simple stuff that provides
the answer.

[TheGreatOne]

This problem is most likely because you pressed the Nostalgy keyboard shortcut that hides the folders panel.

This is usually "L" (this key toggles the folders panel view).

So try just pressing "L". Good luck!