anchor.diff:                                :min-height major :height major)
       (make-space-requirement :min-width  major :width  major
                               :min-height minor :height minor))))
  -
  -
  -
  -(defmethod initialize-instance :before ((pane slider-pane) &rest rest)
  -  (declare (ignore rest))
  -  (setf (slot-value pane 'orientation) :vertical))
  -
  -(defmethod drag-callback ((pane slider-pane) client gadget-id value)
  -  (declare (ignore client gadget-id))
  -  (when (slider-drag-callback pane)
  -    (funcall (slider-drag-callback pane) pane value)))
   
   (defmethod handle-event ((pane slider-pane) (event pointer-enter-event))
     (with-slots (armed) pane
  
positive.code: 
  ;;; 30.4.5 The abstract slider Gadget
  
  (defclass slider-gadget (labelled-gadget-mixin
                           value-gadget
                           oriented-gadget-mixin
                           range-gadget-mixin
                           gadget-color-mixin
                           ;;
                           value-changed-repaint-mixin
                           )
    ()
    (:documentation "The value is a real number, and default value for orientation is :vertical,
  and must never be nil."))
  
  ;;; 30.4.6 The abstract radio-box and check-box Gadgets
  
  
negative.code:     :y-spacing 2))
  
  (defmethod compose-space ((gadget push-button-pane) &key width height)
    (space-requirement+* (space-requirement+* (compose-label-space gadget)
                                              :min-width (* 2 (pane-x-spacing gadget))
                                              :width (* 2 (pane-x-spacing gadget))
  