anchor.diff:  				  (space-requirement-height q)))
   	 (mirror (make-instance 'lisp-scroller :with-frame rect))
   	 ;; Not sure if this is sufficient...
  +	 #+nil
   	 (action-mask (logior #$NSLeftMouseDown
   			      #$NSScrollWheel)))
       (send mirror 'retain)
  
positive.code:   ;; height (or width) of scrollbar        = proportional SIZE of lozenge.
    ;; value                                 = proportional POSITION of lozenge
  
    (let* ((range (- (gadget-max-value gadget) (gadget-min-value gadget)))
  	 (size  (if (eq (gadget-orientation gadget) :vertical)
  		    (bounding-rectangle-height gadget)
  		  (bounding-rectangle-width gadget)))
  
negative.code:     (send mirror :set-target mirror)
      ;; Also need to specify when an action is sent (i.e. which actions
      ;; result in an action being posted)
  ;;;    (send mirror :send-action-on action-mask)
      (send mirror :send-action-on #$NSScrollWheelMask)
      ;; We want continuous actions when we can get them...
      (send mirror :set-continuous #$YES)
      (send mirror :set-action (ccl::@selector "takeScrollerAction:"))
  
      (setf (view-event-mask mirror) +ignores-events+)
      (port-register-mirror (port sheet) sheet mirror)
  