anchor.diff:  	(v-percent (/ height (space-requirement-height (pane-space-requirement box))))
   	(x 0))
       (loop for child in (sheet-children box)
  -	for request = (pane-space-requirement child)
  -	for new-width = (floor (* h-percent (space-requirement-width request)))
  -	for new-height = (floor (* v-percent (space-requirement-height request)))
  -	do (setf (sheet-region child)
  -	     (make-bounding-rectangle x 0 (+ x new-width) new-height))
  -	   (allocate-space child new-width new-height)
  -	   (incf x new-width))))
  +	  for request = (pane-space-requirement child)
  +	  for new-width = (floor (* h-percent (space-requirement-width request)))
  +	  for new-height = (floor (* v-percent (space-requirement-height request)))
  +	  do (progn (setf (sheet-region child)
  +			  (make-bounding-rectangle 0 0 new-width new-height))
  +		    (setf (sheet-transformation child)
  +			  (make-translation-transformation x 0))
  +		    (allocate-space child new-width new-height)
  +		    (incf x new-width)))))
   
   
   ;;; VBOX-PANE class
  
positive.code: 	 (x 0)
  	 (y 0))
      (loop for children in contents
  	  do (loop for child in children
  		   do (setf (sheet-region child)
  			    (make-bounding-rectangle x y (+ x new-width) (+ y new-height)))
  		      (allocate-space child new-width new-height)
  		      (incf x new-width))
          	  (setf x 0)
  		  (incf y new-height))))
  
  
  ;; SPACER PANE
  
negative.code: 	(v-percent (/ height (space-requirement-height (pane-space-requirement box))))
  	(y 0))
      (loop for child in (sheet-children box)
  	  for request = (pane-space-requirement child)
  	  for new-width = (floor (* h-percent (space-requirement-width request)))
  	  for new-height = (floor (* v-percent (space-requirement-height request)))
  	  do (progn (setf (sheet-region child)
  			  (make-bounding-rectangle 0 0 new-width new-height))
  		    (setf (sheet-transformation child)
  			  (make-translation-transformation 0 y))
  		    (allocate-space child new-width new-height)
  		    (incf y new-height)))))
  
  
  ;;; HRACK-PANE class
  