protected function fill_old_values() {
		if ( ! $this->session ) {
			return;
		}

		if ( 0 === count( (array) $this->session->get_old_input() ) ) {
			return;
		}

		foreach ( $this->fields as $key => $field ) {
			if ( ! is_null( $old = $this->session->get_old_input( $key ) ) ) {
				$field->set_value( $old );
			}
		}
	}