[Dovecot] Thread sorting problem

[Greg Trounson]

I've just installed Dovecot on a Debian Sarge machine and am seeing some 
very strange thread sorting.

In Mozilla Mail and Thunderbird on both Fedora and Debian clients my 
threads served up by Dovecot look like this (number denotes message time):

|-11
| `-12
|-2
|-3
|-4
| `-5
|   `-6
|     `-7
|       `-8
|-1
`-9
   `-10

Where the exact same threads served by Sendmail/imap look like this:

|-1
|-2
|-3
|-4
| `-5
|   `-6
|     `-7
|       `-8
|-9
| `-10
|-11
| `-12

Squirrelmail shows the threads correctly in both cases too, so I suspect 
there might be something funny going on with how Thunderbird handles 
Maildir threads.  I notice that Dovecot doesn't support the 
THREAD=ORDEREDSUBJECT capability, might that have something to do with it?

thanks,
Greg