anchor.diff:                 (bed-region      (gadget-bed-region pane))
                  (miny            (bounding-rectangle-min-y bed-region))
                  (maxy            (bounding-rectangle-max-y bed-region))
  -               (thumb-size      (/ +pixie-slider-pane-thumb-size+ (- maxy miny)))
  -               (value (min (gadget-max-value pane)
  -                           (max (gadget-min-value pane)
  -                                (translate-range-value y-new-thumb-top
  -                                              (bounding-rectangle-min-y (gadget-bed-region pane))
  -                                              (bounding-rectangle-max-y (gadget-bed-region pane))
  -                                              (gadget-min-value pane)
  -                                              (+ (gadget-max-value pane) thumb-size))))))
  +               (minv            (gadget-min-value pane))
  +               (maxv            (gadget-max-value pane))
  +               (thumb-size      (* thumb-size (- minv maxv)))
  +               (value           (min maxv
  +                                     (max minv
  +                                          (translate-range-value
  +                                              (+ y-new-thumb-top +pixie-slider-thumb-half-height+)
  +                                              (+ miny +pixie-slider-thumb-half-height+)
  +                                              (- maxy +pixie-slider-thumb-half-height+)
  +                                              minv
  +                                              maxv)))))
   	  (setf (gadget-value pane :invoke-callback nil) value)
   	  (drag-callback pane (gadget-client pane) (gadget-id pane) value)
   	  (dispatch-repaint pane (sheet-region pane)))))))
  
positive.code: 
  (defclass pixie-menu-button-pane (pixie-gadget menu-button-pane) ())
  
  (defmethod handle-event ((pane pixie-menu-button-pane) (event pointer-enter-event))
    (when (slot-value (slot-value pane 'client) 'armed)
      (arm-branch pane)))
  
  (defmethod handle-event ((pane pixie-menu-button-pane) (event pointer-button-press-event))
    (arm-branch pane))
  
  (defmethod handle-event ((pane pixie-menu-button-pane) (event pointer-ungrab-event))
    (destroy-substructure (menu-root pane)))
  
  
  (defmethod handle-repaint ((pane pixie-menu-button-pane) region)
    (declare (ignore region))
    (with-special-choices (pane)
  
negative.code:                 (dispatch-repaint pane (sheet-region pane)))))))))))
  
  (defmethod handle-event ((pane pixie-slider-pane) (event pointer-motion-event))
    (with-slots (dragging drag-delta thumb-size) pane
      (multiple-value-bind (x y)
          (transform-position (vertical-gadget-orientation-transformation pane)
                              (pointer-event-x event) (pointer-event-y event))
  