[Mailman-Users] My Mail Archive Messages Sorted by Thread is not Working Properly

[Wang, Mary Y]

Hi,
I am using Mailman 2.0.6 .  My mail archive sorted by thread is not working
properly.  
This is the how the archive messages sorted by thread is being displayed
now:
---------------------------
*subject A
*subject A
*subject A
*subject B
*subject A
*subject B

What I mean is that archive messages sorted by thread should be displayed
like a tree like the picture depicted below:
-------------------------------
*subject A
   *subject A
   *subject A
   *subject A
   *subject A
*subject B
   *subject B

I don't have a clue.  

Thanks in advance.

Mary 
(562) 797-1545