[Dovecot] Thunderbird Problem - What causes this?

[mouss]

Marc Perkel wrote:
> Strange problem and I'm not sure what's causing it. I'm using IMAP. A 
> new message arives in the inbox. I see it displayed in the message 
> list in bold. I click on the message and it looks like it's reading it 
> by the previous message that was in the window remains and the new 
> message is still bold (unread). However I can then click on an old 
> message and then click on the new message again and it reads.
>
> I have also seen Thunderbird be in a somewhat unresponsive state. You 
> can click on messages and they don't read. But Shutting down 
> Thunderbird and restarting it make it responsive again.
>
> Has anyone seen this?
>

I've seen this with avast and kaspersky (with "heuristics" enabled). 
I've moved to NOD32 since then.