[Dovecot] Old Thunderbird problem - need a fix

[Marc Perkel]

I've been having a Dovecot/Thunderbird problem for about a year now and 
I need a fix. When I restart dovecot everything is fine but as the day 
progresses thing start deteriorating.

When I empty my trash folder it doesn't empty. I get an indication that 
email has arrived in my inbox by the unread message count but can't 
access it. Messages arrive by appear to be empty. Folders that should be 
empty still have message counts showing.

With all of the above problems - restarting dovecot make them all go away.

I am doing something unusual in that I use Exim to directly deliver 
(maildir) to the inbox and other folders. And I have processes that take 
email out of certain folders (spam learning).

Whatever the problem is I think that when I restart Dovecot I'm forcing 
Thunderbird to reconnect. Perhaps the solution is to somehow force 
Thunderbird to have to reconnect every time rather than have a 
persistent connection?

Looking for suggestions. Thanks in advance.