Changing sqimap_mailbox_list_all() to sqimap_mailbox_list() in line 308 of /usr/share/squirrelmail/plugins/avelsieve/edit.php solved this issue for me, although I have no idea why.
Pf -- Pierfrancesco Caci <p...@tippete.net> -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org