anchor.diff:  
   (defmethod* (setf cursor-position) (nx ny (cursor screen-area-cursor))
     (declare (ignore nx ny))
  -  (when (cursor-visibility cursor)
  +  (when (cursor-state cursor)
       (error "screen-area-cursor ~S must not be visible when position is
     set"
   	   cursor))
  
positive.code: 			 :x-position x
  			 :y-position y))))
    (initialize-area-from-buffer area (buffer area))
    (setf (cursor-visibility (cursor area)) t)
    (tree-recompute-extent area))
  
  (defmethod line-text-width ((area simple-screen-area)
  
negative.code: (defmethod redisplay-line ((line screen-line) stream)
    (let* ((medium (sheet-medium stream))
  	 (style (text-style (output-record-parent line))))
      (declare (ignorable style))
      (with-slots (current-contents ascent descent baseline cursor buffer-line)
  	line
        (multiple-value-bind (unchanged
  