anchor.diff:    (set-width-and-height bp width height)
     (let ((border-width (border-pane-width bp))
   	(child (first (sheet-children bp))))
  -    (setf (sheet-region child)
  -      (make-bounding-rectangle border-width border-width
  -			       (- width border-width) (- height border-width)))
  -    (allocate-space child (- width (* 2 border-width)) (- height (* 2 border-width)))))
  +    (when child
  +      (setf (sheet-transformation child)
  +	(make-translation-transformation border-width border-width))
  +      (allocate-space child (- width (* 2 border-width)) (- height (* 2 border-width))))))
  +
   
   ;; RESTRAINING PANE
   
  
positive.code: 		      pane)
    ()
    )
  
  (defmethod compose-space ((basic basic-pane))
    (ask-space-children basic)
  
negative.code:   (set-width-and-height pane width height)
    (let ((child (first (sheet-children pane))))
      (when child
        (setf (sheet-transformation child)
  	(make-translation-transformation 0 0))
        (allocate-space child width height))))
  
  ;; TOP-LEVEL-SHEET
  