code: public void show(ManagementModelNode node, int x, int y) {
          removeAll();
          add(new OperationAction(node, "Real Time Graph", "Plot this attribute in a real time 2D graph."));
          super.show(invoker, x, y);
      }
docs: Show the OperationMenu based on the selected node.
  @param node The selected node.
  @param x The x position of the selection.
  @param y The y position of the selection.