anchor.diff:  
   (defmethod compose-space ((pane scroller-pane) &key width height)
     (declare (ignore width height))
  -  (with-slots (viewport vscrollbar hscrollbar) pane
  +  (with-slots (viewport vscrollbar hscrollbar suggested-width suggested-height) pane
       (if viewport
           (let ((req
                  ; v-- where does this requirement come from?
                  ;     a: just an arbitrary default
   		(make-space-requirement
  -                :width 300 :height 300 :max-width +fill+ :max-height +fill+
  +                :width suggested-width :height suggested-height :max-width +fill+ :max-height +fill+
                   :min-width 30
                   :min-height 30)
   		#+nil
  
positive.code: (defmethod schedule-timer-event ((pane pane) token delay)
    (schedule-event pane (make-instance 'timer-event :token token :sheet pane) delay))
  
  
  
  
negative.code: 	       :accessor scroller-pane-scroll-bar)
     (viewport   :initform nil)
     (vscrollbar :initform nil)
     (hscrollbar :initform nil)
     (suggested-width  :initform 300 :initarg :suggested-width)
     (suggested-height :initform 300 :initarg :suggested-height)))
  
  (defmacro scrolling ((&rest options) &body contents)
    `(let ((viewport (make-pane 'viewport-pane :contents (list ,@contents))))
  