how to constrain column widths in multi-column-list-panel

I would have expected the following code to restricted the column
widths to two characters:

(setf *view* 
      (contain (make-instance 
                'multi-column-list-panel 
                :columns '((:title "col1" :visible-max-width (character 2))
                           (:title "col2" :visible-max-width (character 2)))
                :items '((hello there) 
                         (goodbye friend)))))

But I see no such restriction.  Am I doing something wrong, or is this
a bug?  I am using 4.2.0 on Linux.

regards,
-russ