delete-trailing-whitespace delete non-whitespace characters!!

[Thomas H. Kittelmann]

In GNU Emacs 21.4.2 (i386-mandrake-linux-gnu, X toolkit, Xaw3d scroll 
bars)
 of 2005-04-28 on n4.mandrakesoft.com, modified by Mandrake
configured using `configure  --prefix=/usr --libexecdir=/usr/lib 
--sharedstatedir=/var --with-gcc --with-pop --mandir=/usr/share/man 
--infodir=/usr/share/info --with-x-toolkit i386-mandrake-linux 
--libdir=/usr/lib'
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: en_US
  value of $LC_CTYPE: en_US
  value of $LC_MESSAGES: en_US
  value of $LC_MONETARY: da_DK
  value of $LC_NUMERIC: da_DK
  value of $LC_TIME: en_US
  value of $LANG: en_US
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: nil

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

In my (latex with auctex mode) file I have tilde (~) characters at the end 
of lines. M-x delete-trailing-whitespace removes these along with the 
whitespace.

Cheers,
Thomas