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

        String cwDisclosurePanelFormAdvancedCriteria();

        String cwDisclosurePanelFormDescription();

        String cwDisclosurePanelFormGender();

        String[] cwDisclosurePanelFormGenderOptions();

        String cwDisclosurePanelFormLocation();

        String cwDisclosurePanelFormName();

        String cwDisclosurePanelFormTitle();

        String cwDisclosurePanelName();
      }

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

      /**
       * Initialize this example.
       */
      @Override
      public Widget onInitialize() {
        // Add the disclosure panels to a panel
        VerticalPanel vPanel = new VerticalPanel();
        vPanel.setSpacing(8);
        vPanel.add(createAdvancedForm());

        // Return the panel
        return vPanel;
      }

      /**
       * Create a form that contains undisclosed advanced options.
       */
      private Widget createAdvancedForm() {
        // Create a table to layout the form options
        FlexTable layout = new FlexTable();
        layout.setCellSpacing(6);
        layout.setWidth("300px");
        FlexCellFormatter cellFormatter = layout.getFlexCellFormatter();

        // Add a title to the form
        layout.setHTML(0, 0, constants.cwDisclosurePanelFormTitle());
        cellFormatter.setColSpan(0, 0, 2);
        cellFormatter.setHorizontalAlignment(0, 0,
            HasHorizontalAlignment.ALIGN_CENTER);

        // Add some standard form options
        layout.setHTML(1, 0, constants.cwDisclosurePanelFormName());
        layout.setWidget(1, 1, new TextBox());
        layout.setHTML(2, 0, constants.cwDisclosurePanelFormDescription());
        layout.setWidget(2, 1, new TextBox());

        // Create some advanced options
        HorizontalPanel genderPanel = new HorizontalPanel();
        String[] genderOptions = constants.cwDisclosurePanelFormGenderOptions();
        for (int i = 0; i < genderOptions.length; i++) {
          genderPanel.add(new RadioButton("gender", genderOptions[i]));
        }
        Grid advancedOptions = new Grid(2, 2);
        advancedOptions.setCellSpacing(6);
        advancedOptions.setHTML(0, 0, constants.cwDisclosurePanelFormLocation());
        advancedOptions.setWidget(0, 1, new TextBox());
        advancedOptions.setHTML(1, 0, constants.cwDisclosurePanelFormGender());
        advancedOptions.setWidget(1, 1, genderPanel);

        // Add advanced options to form in a disclosure panel
        DisclosurePanel advancedDisclosure = new DisclosurePanel(
            constants.cwDisclosurePanelFormAdvancedCriteria());
        advancedDisclosure.setAnimationEnabled(true);
        advancedDisclosure.ensureDebugId("cwDisclosurePanel");
        advancedDisclosure.setContent(advancedOptions);
        layout.setWidget(3, 0, advancedDisclosure);
        cellFormatter.setColSpan(3, 0, 2);

        // Wrap the contents in a DecoratorPanel
        DecoratorPanel decPanel = new DecoratorPanel();
        decPanel.setWidget(layout);
        return decPanel;
      }