Some Subjects make Emacs crazy

[jrm@iki.fi (Janne Rinta-Mänty)]

I have a strange problem where selecting an article turns Emacs into
vi (it beeps at every key and the mouse). I suspect it has something
to do with the Subject of the article, because I can reproduce it with
subjects like "öö%" (without the quotes). Tested subjects:

a, b, ..., z, å, ä, ö:       OK
aa, bb, ..., zz, åå, ää, öö: OK
a%, b%, ..., z%, å%, ä%, ö%: OK
aa%, bb%, ..., zz%:          OK
åå%, ää%, öö%:               beep beep beep

Yes, there are subjects like this out there: here is the thread I
couldn't read (it's in Finnish):
<URL:http://groups.google.com/groups?threadm=bc74l3%24aqq%241%40plaza.suomi.net>
There is one article in the thread posted with
Gnus/5.09 (Gnus v5.9.0) Emacs/21.2, so I wonder if this is a Gnus
problem or an Emacs problem?

Debugging a bit seemed to show that everything goes fine until the
modeline of the *Article* buffer is updated: in gnus-set-mode-line
the form

(setq mode-line-buffer-identification
      (gnus-mode-line-buffer-identification (list mode-string)))

shows the problem.

My beeping Emacs and Gnus versions:
GNU Emacs 21.1.1 (i586-pc-linux-gnu, X toolkit) of 2001-10-24
Gnus v5.10.3 (from CVS a week ago)

GNU Emacs 21.1.3 (i686-pc-linux-gnu, X toolkit) of 2001-10-24
Oort Gnus v0.16

Does anybody have any ideas about what is happening here?

-- 
Janne Rinta-Mänty