anchor.diff:  		;; transformation for the pixmap will be the same as that of
   		;; the mirror .
   		(unwind-protect
  -		     (letf (((sheet-parent sheet) nil)
  -			    ((sheet-direct-mirror sheet)
  +		     (letf (((sheet-parent msheet) nil)
  +			    ((sheet-direct-mirror msheet)
   			     (pixmap-mirror pixmap)))
   		       (unwind-protect
   			    (let ((pixmap-region
  
positive.code: 				       user-pixmap-x2 user-pixmap-y2))
  			 (set-native sheet-transform
  				     current-sheet-region
  				     sheet)))
  		  (copy-from-pixmap pixmap 0 0
  				    pixmap-width pixmap-height sheet
  				    user-pixmap-x1 user-pixmap-y1)
  		  (deallocate-pixmap pixmap))))))))))
  
  (defmacro with-double-buffering (((sheet &rest bounds-args)
  
negative.code: 							    user-pixmap-y1
  							    user-pixmap-x2
  							    user-pixmap-y2)))
  			      (set-native sheet-native pixmap-region  msheet)
  			      ;(break)
  			      (with-drawing-options
  				  (medium :ink (medium-background medium))
  