The sidebar in mutt misaligns the number of mails per mailbox when using multibyte characters for names of mailboxes (e.g umlauts etc) or the delimiter string.
It seems something more appropriate for utf8 should replace 'strlen'.
Steps to Reproduce:
1. add mailbox with any multibyte character (umlauts etc) to mutt
2. enable sidebar patch
number of mails in mailboxes misaligned, everything else seems to be fine
right aligned number of mails
please try and report if 1.5.20 exhibits the same problem