(This also applies to 0.13.91, but there's no entry in Bugzilla for
this release yet.)

Sometimes I've seen articles where the most important part of the
text is invisible in Pan.  I think this may have something to do
with Pan's handling of (MIME?) multipart/mixed articles.
Example:  Message-ID: <x54r65dlc0.fsf@lola.goethe.zz> on
comp.os.linux.advocacy, 15 Mar 2003 10:34:55 +0100,
Subject: A message from Terry Porter

Structure:
  [...]
  MIME-Version: 1.0
  Content-Type: multipart/mixed; boundary="=-=-="

  --=-=-=
  Content-Type: text/plain

  [some text, visible in Pan]
  --=-=-=
  Content-Type: message/rfc822
  Content-Disposition: inline

  [copy of an email, invisible in Pan]
  --=-=-=
  Content-Type: text/plain

  [signature, visible in Pan]
  --=-=-=--

Pan doesn't show any indication that the article contains an
attachment, either.  A line count of 83 indicates that something
is wrong, though.

All parts are shown in Sylpheed Claws (0.8.3) and Mozilla (1.3beta).
Mozilla shows a separator between each part.  Claws shows all parts
in the normal body (text) tab, and each part separately in the
"Attachments" tab, all marked as "text/plain".