@Override
 protected ComponentContainer createButtonControls() {
   CrmPreviewFormControlsGenerator<SimpleLead> controlsButton =
       new CrmPreviewFormControlsGenerator<>(previewForm);
   return controlsButton.createButtonControls(
       BACK_BTN_PRESENTED | PREVIOUS_BTN_PRESENTED | NEXT_BTN_PRESENTED | HISTORY_BTN_PRESENTED,
       RolePermissionCollections.CRM_LEAD);
 }
  @Override
  protected ComponentContainer createButtonControls() {
    CrmPreviewFormControlsGenerator<SimpleLead> controlsButton =
        new CrmPreviewFormControlsGenerator<>(previewForm);

    Button convertButton =
        new Button(
            AppContext.getMessage(LeadI18nEnum.BUTTON_CONVERT_LEAD),
            new Button.ClickListener() {
              private static final long serialVersionUID = 1L;

              @Override
              public void buttonClick(ClickEvent event) {
                previewForm.fireExtraAction("convert", beanItem);
              }
            });
    convertButton.setStyleName(UIConstants.THEME_GREEN_LINK);
    convertButton.setIcon(FontAwesome.FLASK);
    controlsButton.insertToControlBlock(convertButton);

    return controlsButton.createButtonControls(RolePermissionCollections.CRM_LEAD);
  }