I have several filters that sort my incoming mail into several boxes. I
would like for those boxes to appear just below the inbox so I don't
have to scan through all my boxes looking for those with new mail. I
can't find any means of reordering my mailboxes, other than prefixing
the ones of interest with something like "a_" to force them to sort to
the top.
Assuming account type POP3.
Just make those folders children of the Inbox, rather than children of
the "On this Computer" node. If you already do, make every other folder
not children of Inbox...