anchor.diff:                      :drag-callback #'slider-updated-callback)
             (scale-slider :slider
                           :value 1
  -                        :show-value t
  +                        :show-value-p nil
                           :orientation :horizontal
                           :min-value 0.1
                           :max-value 5
  
positive.code:                         :drag-callback #'slider-updated-callback)
            (x-skew-slider :slider
                           :value 0
                           :show-value t
                           :orientation :horizontal
                           :min-value -1
                           :max-value 1
  
negative.code:           :accessor image-transform-demo/image))
    (:panes (image-demo :application
                        :display-function 'display-image-demo
                        :scroll-bars :both
                        :incremental-redisplay t)
            (rot-slider :slider
                        :value 0
                        :show-value-p nil
                        :orientation :horizontal
                        :min-value 0
                        :max-value (* pi 2)
  