[horde] imp don't display some messages inline

[Andreas Schulze]

Hello,

from a cronjob I got a message which imp (6.1.3) does not display at all.
I simple get the info "There are no parts that can be shown inline."
But in fact it's a simple text message.

message that fail to display inline
BEGIN ---------------
Return-Path: <root at example.org>
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: quoted-printable
Subject: Unattended-Upgrades-Ergebnis fuer »foo«
To: root at example.org
Message-Id: <3c2rvb4QNQzbP8 at example.org>
Date: Sun, 28 Jul 2013 06:41:14 +0200 (CEST)
From: root at example (root)

body with german "Umlaut" ü (utf-8 encoded)

erlaubte Ursprünge sind: ['o=debian.example.org,a=stable',  
'o=debian-foo.example.org,a=stable',  
'origin=Debian,archive=stable,label=Debian-Security']

an other line
END ---------------

message with one line removed and imp will display inline
BEGIN ---------------
Return-Path: <root at example.org>
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: quoted-printable
Subject: Unattended-Upgrades-Ergebnis fuer »foo«
To: root at example.org
Message-Id: <3c2rvb4QNQzbP8 at example.org>
Date: Sun, 28 Jul 2013 06:41:14 +0200 (CEST)
From: root at example (root)

body with german "Umlaut" ü (utf-8 encoded)


an other line
END ---------------

to prove only one line is removed:
$ diff fail success
13d12
< erlaubte Ursprünge sind: ['o=debian.example.org,a=stable',  
'o=debian-foo.example.org,a=stable',  
'origin=Debian,archive=stable,label=Debian-Security']
$

Is this a bug or some kind of "special misconfigured"
Andreas