[BUG]What does this mean:"Mention that multibyte characters don't work as marks."?

[zrr <beijing_2008_gold@yahoo.com.cn>]

Hello,

    I have reported this problem several days ago that the most
    recent Gnus can't mark articles in the summary buffer.
    Eventually, I went back to the old version.  Today, I checked
    out the Emacs CVS tree and encountered this problem again.

    Perhaps I had ignored an important factor in my first bug
    report, that my emacs is emacs-unicode-2 branch, because same
    version Gnus works perfectly in emacs trunk.

    I checked Gnus ChangeLog and find this line:

       * gnus-sum.el: Mention that multibyte characters don't work as marks.

    What does this mean? Does it indicate following lines in the
    'gnus-sum.el'?

      ;; FIXME: Although the custom type is `character' for the following variables,
      ;; using multibyte characters (Latin-1, UTF-8) doesn't work.  -- rs

    however, I have never customized this variables.      
    
    I managed to load the old 'gnus-sum.el', as I expected, it
    works.  I also performed a diff on two version 'gnus-sum.el' and
    find out this problem is caused by the change of
    'gnus-update-summary-mark-positions'. 

    Although there are very few people use unicode-2 branch now,  I
    think this bug should be solved sooner or later.


Regards!
Tang