[Dovecot] Thunderbird or Dovecot bug? (multiple keywords)

[Troy Engel]

Here's a strange one. I have a user who's using Thunderbird 2.0.0 and 
assigning multiple tags (keywords) to emails, which are getting "lost" 
(I'll explain) when he leaves the folder and comes back. I can reproduce 
this on *his* account myself, but cannot reproduce it on *my* account 
(separate new TBird 2.0.0 profiles on Windows XP).

Use the two TBird default tags 'Important' and 'Work' for all these 
tests, which it refers to as $Label1 and $Label2 in IMAP-keywords land. 
If I go into my account, label an email with both tags, it sticks -- I 
can click on Drafts then back to Inbox, and both tags/keywords still 
show in the client.

If I go into his account, add the two tags, then click on Drafts and 
back on Inbox, only the *second* tag (Work, $Label2) shows. If I remove 
that tag, then the first tag (Important, $Label1) immediately pops up!

On the backend the actual Maildir files match the dovecot-keywords and 
have the correct letter appended in both cases - so, in his account when 
the email only shows one tag, the physical mail file has the letters for 
two tags. So Thunderbird should be showing both tags, like it does in my 
account where everything is working correctly.

This leads me to believe that the problem has something to do with the 
difference of dovecot-keywords content, and the interaction TBird has 
with Dovecot. My account, working correctly, looks like:

dovecot-keywords:
   0 $Forwarded
   1 $MDNSent
   2 $Label2
   3 $Label1

file:
   Maildir/cur/1178712608.H529732P11686.yak.fluid.com:2,RSdc

...which matches, d=$Label1 (Important), c=$Label2 (Work) and TBird is 
displaying the email as having both tags - all is well and good. Now, 
his account looks like:

dovecot-keywords:
   0 Junk
   1 NonJunk
   2 $Label4
   3 $Label1
   4 $Label2
   5 $Label3
   6 $Label5

file:
   Maildir/cur/1178728930.P28392Q0M960111.yak.fluid.com:2,RSbde

...again, everything matches on the server; yet, it Thunderbird is only 
displaying $Label2 (d,3). I also noticed something interesting, even if 
I have the TB 'Junk Controls' completely disabled on his account, and 
remove all tags using the menu option, that file still retains the 'b' 
(NonJunk) tag in the filename:

   Maildir/cur/1178728930.P28392Q0M960111.yak.fluid.com:2,RSb

All this long-winded explanation leads me to believe that somehow the 
difference in dovecot-keywords is causing this problem, but what I can't 
tell is who's problem it is -- Dovecot, or Thunderbird?

Thoughts welcome,
-te

PS: all the normal things tried like deleting the dovecot index files, 
Thunderbird cache files and profiles, etc.

-- 
Troy Engel | Systems Engineer
Fluid, Inc | http://www.fluid.com