anchor.diff:      (if width-p
   	(if (or (not width) (zerop width)) (get-width pane) width)
           (if (or (not height) (zerop height)) (get-height pane) height))))
  -
  -(defun set-width-and-height (rectangular-sheet width height)
  -  (multiple-value-bind (x1 y1)
  -      (rectangle-edges* (sheet-region rectangular-sheet))
  -    (setf (sheet-region rectangular-sheet)
  -	  (make-bounding-rectangle x1 y1 (+ x1 width) (+ y1 height)))))
   
   (defun make-extremums-children-ratio (pane children &key (width t) (height t))
     (with-slots (sorted-max-w-r sorted-max-h-r sorted-min-w-r sorted-min-h-r) pane
  
positive.code:   (make-extremums-children-ratio rack (sheet-children rack) :height nil))
  
  (defmethod allocate-space ((rack hrack-pane) width height)
    (set-width-and-height rack width height)
    (allocate-space-internal rack width)
    (loop for child in (sheet-children rack)
  	for nw = (slot-value child 'new-width)
  	and x = 0 then (+ x (round nw))
  	do (multiple-value-bind (x1 y1)
  	       (bounding-rectangle* (sheet-region child))
  	     (setf (sheet-transformation child)
  		   (make-translation-transformation (- x x1) (- y1))))
  	   (allocate-space child nw height)))
  
  ;;; VRACK-PANE
  
negative.code:         (make-space-requirement))))
  
  (defmethod allocate-space ((pane scroller-pane) width height)
    (resize-sheet pane width height)
    (with-slots (viewport vscrollbar hscrollbar) pane
      (when viewport
        (setf (sheet-transformation viewport)
  