code: public Button addMenuEntry(String label, Resource icon) {
  
          Button button = new Button(label, icon);
          button.setPrimaryStyleName(OpenCmsTheme.VERTICAL_MENU_ITEM);
          addComponent(button);
          return button;
      }
docs: Adds an entry to the menu, returns the entry button.<p>
  
  @param label the label
  @param icon the icon
  
  @return the entry button