code: protected boolean isHideButtonAdvanced() {
  
          I_CmsDialogHandler handler = OpenCms.getWorkplaceManager().getDialogHandler(getDialogHandler());
          CmsParameterConfiguration handlerParams = handler.getConfiguration();
          if ((handlerParams != null) && handlerParams.containsKey(PARAM_HIDEADVANCED)) {
              // checks if "hideadvanced" is set to true
              boolean isHideAdvancedSet = false;
              List<String> hAdvanced = handlerParams.getList(PARAM_HIDEADVANCED);
              if (!hAdvanced.isEmpty()) {
                  isHideAdvancedSet = Boolean.valueOf(hAdvanced.get(0)).booleanValue();
              }
              if (isHideAdvancedSet) {
                  // if user has the role root admin
                  if (OpenCms.getRoleManager().hasRole(getCms(), CmsRole.ROOT_ADMIN)) {
                      return false;
                  }
                  if (handlerParams.containsKey(PARAM_SHOWGROUP)) {
                      // check if user is one of the configured groups
                      CmsUser currentUser = getCms().getRequestContext().getCurrentUser();
                      List<String> confGroups = handlerParams.getList(PARAM_SHOWGROUP);
                      for (String groupName : confGroups) {
                          try {
                              if (getCms().userInGroup(currentUser.getName(), groupName)) {
                                  return false;
                              }
                          } catch (CmsException e) {
                              LOG.error(e.getLocalizedMessage(), e);
                          }
                      }
                  }
                  return true;
              }
          }
          return false;
      }
docs: Checks the optional parameters of the handler configuration. <p>
  
  Decides if the "advanced" button should be shown or not.
  The "advanced" button is shown if no parameters are given (default)
  or the "hideadvanced" attribute is set to false. The "advanced" button
  is hidden only, if "hideadvanced" is true and the user is not a member
  of the specified user groups.
  
  @return  false if the "advanced" button is shown (default) <br>
  true if the "advanced" button is hidden