def after_painting(flag = true, & block)
      if flag
        @peer.after_paint_action = PaintAction.new(& block)
      else
        @peer.after_paint_action = nil
      end
    end
def after_painting(flag = true, & block)
      if flag
        @peer.after_paint_action = PaintAction.new(& block)
      else
        @peer.after_paint_action = nil
      end
    end
A hook to invoke behavior after a Prop is painted.