public void showCloseButtonPanel() {
    CaptionPanel closePanel = new CaptionPanel(constants.closeTitle());
    closePanel.setWidth("185px");

    VerticalPanel vp = new VerticalPanel();
    vp.setWidth("100%");
    vp.setHorizontalAlignment(HasHorizontalAlignment.ALIGN_CENTER);

    closeButton = new Button(constants.close());

    vp.add(closeButton);

    closePanel.setContentWidget(vp);

    builderContent.add(closePanel);
  }