[plt-scheme] Dragable panels

Hi,

I have some problems with the dragable panels from framework. 
I am working in DrScheme v208. I have included a little code
which
hopefully demonstrates the problem. In the code there is a
commented
line. If I uncomment it, then DrScheme always reports that
"the percentages would violate minimum size requirements of
the children". I did not manage to specify any valid value,
not even half-
half. The other problem is related to the dragging. In the
created
window when I drag downwards, then there is a limit, which
is probably
the minimum size of the text-field. However upwards I can
drag to the
top of the window, and the program does not stop me.
Furthermore 
when I do this then the bottom text-field will overlap the
canvas and
I cannot do any more dragging, because the mouse cannot
sense the
dragging bar anymore. I suspect ther is some kind of mistake 
somewhere.

Can anyone help me with these problems? Thank you very much.

Peter Ivanyi

-------------------------------------------------------------------------

(module test mzscheme
  (require (lib "class.ss") 
         (lib "mred.ss" "mred")
         (lib "framework.ss" "framework"))

  (define win (new frame% (label "test") 
                                           (min-width 500)
(min-height 500)))
  (define vbox (new panel:vertical-dragable% (parent win)))
  (define hbox (new horizontal-panel% (parent vbox)))

  (define my%
    (class canvas% ()
      (define/override (on-size width height)
        (display (send vbox get-percentages))(newline))
      (super-instantiate () ) ) )
  
  (define gr  (new my% 
                   (parent hbox)
                   (min-width 100) (min-height 100)))
  (define option (new group-box-panel% (parent hbox)
                                    (stretchable-width #f)
                                    (label "Option menu")))
  (define history (new text-field%
                             (callback void)
                             (style '(multiple))
                             (label "")
                             (enabled #t)
                             (parent vbox)))
  ;;;;; (send vbox set-percentages '(6/10 4/10))
  (send win show #t)
)