Unexpected filtering of headers

[Andreas Schmidt <andy space wh1 tu-dresden de>]

Hi,

I just noticed that one of my filters doesn't seem to work as expected.  
I've set up a filter to move mails matching the expression  
"postmaster localhost" in user header "X-Original-To" to an mbox named  
"Postmaster". Currently, there is one message in the Inbox that this  
filter should match:

> From somebody some where  Thu Jun 24 08:48:59 2004
Return-Path: <somebody some where>
X-Original-To: pc localhost
X-Original-To: postmaster localhost

Alas, it does nothing. Now, when I change the filter to match  
"pc localhost", it moves this mail and all others from my Inbox to  
Postmaster.
The problem seems to be that the filtering routine only looks for the  
first occurence of a given header. That's okay for uniq headers like  
From: or To:, but it just doesn't work for headers that could get  
inserted at any relay a mail is passing through. Would it be possible  
to  grep through the complete header part for occurences of (at least)  
user headers?

Best regards,

Andreas