static function isFormSubmission() {

		if ( empty( $_REQUEST['page'] ) ) {
			return false;
		}

		if ( 'pb_catalog' !== $_REQUEST['page'] ) {
			return false;
		}

		if ( $_SERVER['REQUEST_METHOD'] === 'POST' ) {
			return true;
		}

		if ( static::isCurrentAction( 'add' ) || static::isCurrentAction( 'remove' ) ) {
			return true;
		}

		return false;
	}