anchor.diff:  		   :accessor gadget-show-value-p)
      (decimal-places :initform 0
                      :initarg :decimal-places
  -                   :reader slider-decimal-places)))
  +                   :reader slider-decimal-places)
  +   (number-of-quanta :initform nil
  +                     :initarg :number-of-quanta
  +                     :reader slider-number-of-quanta)))
   
   
   (defmethod initialize-instance :before ((pane slider-pane) &rest rest)
  
positive.code:   (multiple-value-bind (x1 y1 x2 y2) (bounding-rectangle* (sheet-region pane))
      (multiple-value-bind (good-dim1 good-dim2)
  	(if (eq (gadget-orientation pane) :vertical)
  	    ; vertical orientation
  	    (values (+ y1 (ash slider-button-short-dim -1))
  		    (- y2 (ash slider-button-short-dim -1)))
  	    ; horizontal orientation
  	    (values (+ x1 (ash slider-button-short-dim -1))
  		    (- x2 (ash slider-button-short-dim -1))))
        (+ (gadget-min-value pane)
  	 (/ (* (gadget-range pane) (- (max good-dim1 (min dim good-dim2)) good-dim1))
  	    (- good-dim2 good-dim1))))))
  
  (defun format-value (value decimal-places)
    (if (<= decimal-places 0)
  
negative.code: (defmethod handle-event ((pane slider-pane) (event pointer-button-press-event))
    (with-slots (armed) pane
       (when armed
         (setf armed ':button-press))))
  
  (defmethod handle-event ((pane slider-pane) (event pointer-motion-event))
    (with-slots (armed) pane
  