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

        String cwVerticalPanelDescription();

        String cwVerticalPanelName();
      }

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

      /**
       * Initialize this example.
       */
      @Override
      public Widget onInitialize() {
        // Create a Vertical Panel
        VerticalPanel vPanel = new VerticalPanel();
        vPanel.setSpacing(5);

        // Add some content to the panel
        for (int i = 1; i < 10; i++) {
          vPanel.add(new Button(constants.cwVerticalPanelButton() + " " + i));
        }

        // Return the content
        vPanel.ensureDebugId("cwVerticalPanel");
        return vPanel;
      }