anchor.diff:  (defclass slider-pane (slider
                          gadget-color-mixin
                          value-changed-repaint-mixin
  -                       activate/deactivate-repaint-mixin
  -                       basic-pane)
  +                       activate/deactivate-repaint-mixin)
     ())
   
   (defmethod compose-space ((pane slider-pane) &key width height)
  
positive.code: (defclass check-box-pane (check-box
                            rack-layout-mixin
                            activate/deactivate-repaint-mixin
                            sheet-multiple-child-mixin
                            basic-pane)
    ()
    (:default-initargs :background *3d-normal-color*))
  
  
negative.code: (defclass radio-box-pane (radio-box
                            activate/deactivate-repaint-mixin
                            rack-layout-mixin
                            sheet-multiple-child-mixin)
    ()
    (:default-initargs :background *3d-normal-color*))
  
  