# File ../lib/fox/undolist.rb, line 320
    def onUpdUndo(sender, sel, ptr)
      if canUndo?
        sender.handle(self, MKUINT(FXWindow::ID_ENABLE, SEL_COMMAND), nil)
      else
        sender.handle(self, MKUINT(FXWindow::ID_DISABLE, SEL_COMMAND), nil)
      end
      return 1
    end