odd behavior with empty sentbox

[Jack <ostroffjh users sourceforge net>]

Hello all,

It's been quiet here, so I thought I'd post about a new mystery which  
I've been noticing for the past week or so.  I have no real idea if  
this is due to some recent change (git master) or if I just never  
tripped over it before.

My Sentbox folder is mapped to a mbox file sent-mail in my main mail  
directory.  If I delete all messages from that folder and expunge them,  
everthing seems fine.  However, if I then quit balsa and restart it,  
the Unread and Total numbers in the mailbox pane are blank (not 0) and  
Balsa thinks there is an unread message in that folder.  If I click  
"Next unread" Balsa opens that folder, which is empty, the message  
numbers stay blank, and the mailbox name in the tab is shown in bold.   
In addition, if I hit "Next unread" again, nothing happens, even if  
there is an unread message elsewhere.  If I select a different folder  
and hit "Next unread" it may go back to Sentbox or the other folder  
with an unread message - I assume which it chooses depends on the order  
in which it checks all mailboxes for unread messages.

My assumption here is that when the last message is deleted from  
sent-mail, rather than creating an empty file, the file is just deleted  
(or at least not created when it is "rewritten" with no messages.

I have not yet dug into the code to see if I can actually confirm any  
of these assumptions.

Thanks for any thoughts or suggestions.

Jack