anchor.diff:  					   (pointer-event-x event))))
         (dispatch-repaint pane (sheet-region pane)))))
   
  -#+NIL
  -(defmethod handle-event ((pane slider-pane) (event window-repaint-event))
  -  (dispatch-repaint pane (sheet-region pane)))
   
   (defmethod convert-position-to-value ((pane slider-pane) dim)
     (multiple-value-bind (x1 y1 x2 y2) (bounding-rectangle* (sheet-region pane))
  
positive.code:                      (setf (gadget-client c) pane)
                       c))
                   choices)))
      (mapc (curry #'sheet-adopt-child pane) children)
      (reorder-sheets pane children) ))
  
  ;;; ------------------------------------------------------------------------------------------
  ;;;  30.4.7 The concrete list-pane and option-pane Gadgets
  
negative.code: ;;; 30.4.1 The concrete push-button Gadget
  
  (defclass push-button-pane  (push-button
                               labelled-gadget-mixin
                               changing-label-invokes-layout-protocol-mixin
                               arm/disarm-repaint-mixin
                               enter/exit-arms/disarms-mixin
  