No thread indicator

To: Mutt List <mutt-users@xxxxxxxx>
Subject: No thread indicator
From: Rem P Roberti <rem@xxxxxxxxxx>
Date: Tue, 16 Oct 2007 13:36:37 -0700
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I just recently noticed that I no longer have threads indicated in the
the index.  I'm not sure how that happened but I would like to fix it.  

Rem