[MlMt] Let the Mail-preview show particular header-parts

[Niels Kobschätzki]

Hi,

in the default setting the preview of a mail (i.e. in the 
widescreen-view that would be the third pane) the following header-parts 
are shown:
 From:
Subject:
Date:
To:

Is there a way to add a header-part like "Delivered-to"?
Is there a way to show there to which imap-source a mail belongs?

Niels