Problem displaying multipart/alternative messages

[Michael Piotrowski <mxp@dynalabs.de>]

Hi,

Using the current git version of Gnus on XEmacs 21.4.22, I'm now getting
the error "Selecting deleted or non-existent buffer" when trying to view
a multipart/alternative message (as produced by, e.g., Apple Mail or
Microsoft Outlook):

#v+
Debugger entered--Lisp error: (error "Selecting deleted or non-existent buffer")
  mm-preferred-alternative-precedence(((#<buffer " *mm*<2>"> ("text/plain" ... ... ...) quoted-printable nil nil nil nil nil) ("multipart/related" (#<buffer " *mm*<4>"> ... quoted-printable nil nil nil nil nil) (#<buffer " *mm*<5>"> ... base64 nil ... nil nil "<169B2FFF-3C89-4C5A-BFAF-D4BF383302CD@local>"))))
  mm-preferred-alternative(((#<buffer " *mm*<2>"> ("text/plain" ... ... ...) quoted-printable nil nil nil nil nil) ("multipart/related" (#<buffer " *mm*<4>"> ... quoted-printable nil nil nil nil nil) (#<buffer " *mm*<5>"> ... base64 nil ... nil nil "<169B2FFF-3C89-4C5A-BFAF-D4BF383302CD@local>"))))
  gnus-mime-display-alternative(((#<buffer " *mm*<2>"> ("text/plain" ... ... ...) quoted-printable nil nil nil nil nil) ("multipart/related" (#<buffer " *mm*<4>"> ... quoted-printable nil nil nil nil nil) (#<buffer " *mm*<5>"> ... base64 nil ... nil nil "<169B2FFF-3C89-4C5A-BFAF-D4BF383302CD@local>"))) nil nil 1)
  gnus-mime-display-part(("multipart/alternative" (#<buffer " *mm*<2>"> ("text/plain" ... ... ...) quoted-printable nil nil nil nil nil) ("multipart/related" (#<buffer " *mm*<4>"> ... quoted-printable nil nil nil nil nil) (#<buffer " *mm*<5>"> ... base64 nil ... nil nil "<169B2FFF-3C89-4C5A-BFAF-D4BF383302CD@local>"))))
  gnus-display-mime()
  gnus-article-prepare-display()
  gnus-article-prepare(1860 nil)
  gnus-summary-display-article(1860 nil)
  gnus-summary-select-article(nil force)
  gnus-summary-show-article(nil)
  call-interactively(gnus-summary-show-article)
#v-

I have this in my .gnus:

#v+
;;; Discourage text/html alternatives
(setq mm-discouraged-alternatives '("text/html"))

;;; Don't render HTML, even if there's no alternative
;;; http://my.gnus.org/faq/html-nochunks/#id2491979
(setq mm-automatic-display (remove "text/html" mm-automatic-display))
#v-

So I first thought it may be a configuration incompatibility, but the
error also occurs with the default settings.

Any ideas?

Thanks in advance!

-- 
Dr.-Ing. Michael Piotrowski, M.A.                   <mxp@dynalabs.de>
Public key at <http://www.dynalabs.de/mxp/pubkey.txt> (ID 0x1614A044)