[MlMt] Mailbox sidebar - how to turn on/off it displaying

[John Cooper]

Doug Knapman via mailmate wrote (at 8:34 AM on Wednesday, September 13, 2023):

> Mailmate is no longer showing the sidebar on the left showing all the configured mailboxes.  How do I get it back and turn it off when I want to focus on one mailbox?

With main window (not a message window) open:

View > Layout > Show Mailboxes

Note the associated shortcut. Could you have pressed it by mistake?