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

    String cwCustomButtonName();

    String cwCustomButtonPush();

    String cwCustomButtonToggle();
  }

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

  /**
   * Initialize this example.
   */
  @Override
  public Widget onInitialize() {
    // Create a panel to layout the widgets
    VerticalPanel vpanel = new VerticalPanel();
    HorizontalPanel pushPanel = new HorizontalPanel();
    pushPanel.setSpacing(10);
    HorizontalPanel togglePanel = new HorizontalPanel();
    togglePanel.setSpacing(10);

    // Combine all the panels
    vpanel.add(new HTML(constants.cwCustomButtonPush()));
    vpanel.add(pushPanel);
    vpanel.add(new HTML("<br><br>" + constants.cwCustomButtonToggle()));
    vpanel.add(togglePanel);

    // Add a normal PushButton
    PushButton normalPushButton = new PushButton(
        new Image(Showcase.images.gwtLogo()));
    normalPushButton.ensureDebugId("cwCustomButton-push-normal");
    pushPanel.add(normalPushButton);

    // Add a disabled PushButton
    PushButton disabledPushButton = new PushButton(
        new Image(Showcase.images.gwtLogo()));
    disabledPushButton.ensureDebugId("cwCustomButton-push-disabled");
    disabledPushButton.setEnabled(false);
    pushPanel.add(disabledPushButton);

    // Add a normal ToggleButton
    ToggleButton normalToggleButton = new ToggleButton(
        new Image(Showcase.images.gwtLogo()));
    normalToggleButton.ensureDebugId("cwCustomButton-toggle-normal");
    togglePanel.add(normalToggleButton);

    // Add a disabled ToggleButton
    ToggleButton disabledToggleButton = new ToggleButton(
        new Image(Showcase.images.gwtLogo()));
    disabledToggleButton.ensureDebugId("cwCustomButton-toggle-disabled");
    disabledToggleButton.setEnabled(false);
    togglePanel.add(disabledToggleButton);

    // Return the panel
    return vpanel;
  }