public function wrapper_class_names() {

		$wrapper_class_names = array(
			'uix-panel-inside',
		);

		if ( $this->child_count() > 1 ) {
			$wrapper_class_names[] = 'uix-has-tabs';

			if ( ! empty( $this->struct['top_tabs'] ) ) {
				$wrapper_class_names[] = 'uix-top-tabs';
			}
		}

		return implode( ' ', $wrapper_class_names );
	}