I wanted to start using (neo)mutt's sidebar and I wanted a way of separating groups of mail folders in the list. To achieve that I interleaved a couple of fake "divider" folder names. It looks like this:

  Screenshot of neomutt with sidebar

Screenshot of neomutt with sidebar

This was spurred on by an attempt to revamp my personal organisation.

I've been using mutt for at least 20 years (these days neomutt), which, by default, does not show you a list of mail folders all the time. The default view is an index of your default mailbox, from which you can view a mail (pager view), switch to a mailbox, or do a bunch of other things, some of which involve showing a list of mailboxes. But the list is not omnipresent. That's somewhat of a feature, if you believe that you don't need to see that list until you are actually planning to pick from it.

There's an old and widespread "sidebar" patch for mutt (which neomutt ships out of the box). It reserves a portion of the left-hand side of the terminal to render a list of mailboxes. It felt superfluous to me so I never really thought to use it, until now: I wanted to make my Inbox functional again, and to achieve that, I needed to move mail out of it which was serving as a placeholder for a particular Action, or as a reminder that I was Waiting on a response. What was stopping me was a feeling I'd forget to check other mailboxes. So, I need to have them up in my face all the time to remind me.

Key for me, to make it useful, is to control the ordering of mailboxes and to divide them up using the interleaved fake mailboxes. The key configuration is therefore

set sidebar_sort_method = 'unsorted'
mailboxes =INBOX =Action =Waiting
mailboxes '=   ~~~~~~~~' # divider

My groupings, for what it's worth, are: the key functional mailboxes (INBOX/Action/Waiting) come first; last, is reference ('2023' is the name of my current Archive folder; the other folders listed are project-specific reference and the two mailing lists I still directly subscribe to). Sandwiched in between is currently a single mailbox which is for a particular project for which it makes sense to have a separate mailbox. Once that's gone, so will that middle section.

For my work mail I do something similar, but the groupings are

  1. INBOX/Action/Waiting
  2. Reference (Sent Mail, Starred Mail)
  3. More reference (internal mailing lists I need to closely monitor)
  4. Even more reference (less important mailing lists)

As with everything, these approaches are under constant review.