anchor.diff:      (unless armed
         (armed-callback pane (gadget-client pane) (gadget-id pane)))
       (setf armed ':button-press)
  -    (push-highlight-button pane)))      
  +    (setf (gadget-current-color pane) (gadget-pushed-and-highlighted-color pane))
  +    (dispatch-repaint pane (sheet-region pane))))     
         
   (defmethod handle-event ((pane toggle-button-pane) (event pointer-button-release-event))
     (with-slots (armed) pane
  
positive.code:    (active-p;; [Arthur] I'm not so sure about the value for :initform.
      ;; Maybe T is better? Or maybe we should call
      ;; ACTIVATE-GADGET after creating a gadget?
      :initform nil 
      :reader gadget-active-p)
     (armed :initform nil) ))
  
  
negative.code: ;;
  
  (defclass gadget-color-mixin ()
    ((normal :type color
  	   :initform +gray50+
  	   :initarg :normal
  	   :accessor gadget-normal-color)
     (highlighted :type color
  		:initform +gray75+
  		:initarg :highlighted
  		:accessor gadget-highlighted-color)
     (pushed-and-highlighted :type color
  			   :initform +gray25+
  			   :initarg :pushed-and-highlighted
  			   :accessor gadget-pushed-and-highlighted-color)
     (current-color :type color
  		  :accessor gadget-current-color))
    (:documentation "This class define the gadgets colors."))
  
  (defmethod initialize-instance :after ((gadget gadget-color-mixin) &rest args)
    (declare (ignore args))
    (setf (gadget-current-color gadget) (gadget-normal-color gadget)))
  
  (defmethod define-gadget-color ((gadget gadget-color-mixin) x1 y1 x2 y2)
    (draw-rectangle* gadget x1 y1 x2 y2 :ink (gadget-current-color gadget) :filled t))
  
  
  ;;
  