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

    String cwVerticalPanelDescription();

    String cwVerticalPanelName();
  }

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