No support for listing of unseen messages per mailbox (not per server)
Plugin has messed basic terminology: mailbox is a folder on a server (due to rfc):
The Internet Message Access Protocol Version 4rev2 (IMAP4rev2) allows
a client to access and manipulate electronic mail messages on a
server. IMAP4rev2 permits manipulation of mailboxes (remote message
folders)
So bulk renaming is necessary.
And xfce_mailwatch_signal_new_messages()
pass total per server new_messages
count into _XfceMailwatch.mailboxes
instead of _XfceMailwatch.servers.mailboxes
.