      /**
       * The constants used in this Content Widget.
       */
      public static interface CwConstants extends Constants,
          ContentWidget.CwConstants {
        String cwFlowPanelDescription();

        String cwFlowPanelItem();

        String cwFlowPanelName();
      }

      /**
       * An instance of the constants.
       */
      private CwConstants constants;

      /**
       * Initialize this example.
       */
      @Override
      public Widget onInitialize() {
        // Create a Flow Panel
        FlowPanel flowPanel = new FlowPanel();
        flowPanel.ensureDebugId("cwFlowPanel");

        // Add some content to the panel
        for (int i = 0; i < 30; i++) {
          CheckBox checkbox = new CheckBox(constants.cwFlowPanelItem() + " " + i);
          checkbox.addStyleName("cw-FlowPanel-checkBox");
          flowPanel.add(checkbox);
        }

        // Return the content
        return flowPanel;
      }