docs: private void validateDialog() throws Exception {
  
          CmsResource.checkResourceName(m_sitename);
          m_sitename = ensureFoldername(m_sitename);
          if (CmsStringUtil.isEmptyOrWhitespaceOnly(m_site.getServer())) {
              // the server's URL must not be empty or null
              throw new CmsException(Messages.get().container(Messages.ERR_SERVER_URL_NOT_EMPTY_0));
          }
      }