New mail in folders notification?

[Adam Tauno Williams]

On Sun, 2010-01-31 at 20:04 +0100, Garry wrote:
> Anyway, I've now noticed that Thunderbird doesn't display the folders as
> new with the number of mails in them ... at least not all of them ...
> sometimes it will correctly show a new incoming mail, while other (most)
> times, I need to go to the folder ...
> Is this a basic problem/shortcoming of the MUA, 

Yes.