public function updateCMSFields(FieldList $fields)
    {
        $controller       = Controller::curr();
        $isEditController = $controller instanceof CMSPageEditController;
        $xfrontEndAdmin   = filter_input(INPUT_SERVER, 'HTTP_X_FRONT_END_ADMIN') == "true";
        $frontEndAdmin    = $controller->getRequest()->getVar('frontEndAdmin') == "true";

        if ($isEditController && ($xfrontEndAdmin || $frontEndAdmin)) {
            $fields->removeFieldFromTab("Root.Main", "Content");
        }
    }