anchor.diff:  	    (draw-line* pane x1 y1 x2 y1 :ink +black+)
   	    (draw-line* pane x1 y1 x1 y2 :ink +black+)
   	    (draw-line* pane x1 y2 x2 y2 :ink +white+)
  -	       (draw-line* pane x2 y1 x2 y2 :ink +white+))
  +	    (draw-line* pane x2 y1 x2 y2 :ink +white+))
   	  (progn
   	    (draw-line* pane x1 y1 x2 y1 :ink +white+)
   	    (draw-line* pane x1 y1 x1 y2 :ink +white+)
  
negative.code: 
  (defclass text-field-pane (text-field clim-stream-pane) ())
  
  (defmethod handle-event ((pane text-field-pane) (event window-repaint-event))
    (dispatch-repaint pane (sheet-region pane)))
  
  (defmethod repaint-sheet ((pane text-field-pane) region)
    (declare (ignore region))
    (let ((fun (pane-display-function pane)))
      (when fun
        (funcall fun pane))))
  
  (defmethod (setf gadget-value) :after (value (pane text-field-pane) &key invoke-callback)
    (declare (ignore value invoke-callback))
    (window-clear pane))
  
  (defclass clx-text-field-pane (text-field-pane) ())
  
  
  