A typecho standalone page template,

<?php
/**
 * 
 *
 * @package custom
 */
if (!defined("__TYPECHO_ROOT_DIR__")) exit; ?>
<?php $this->need("header.php"); ?>
<h2 class="page-title"><?php $this->title() ?></h2>
<hr>
<?php $this->widget("Widget_Metas_Category_List")->parse("<a href="{permalink}"> {name}   ({count})</a>"); ?>
<?php $this->need("footer.php"); ?>

where header.php has been called once

$this->widget("Widget_Metas_Category_List")->parse("<a href="{permalink}">{name}  ({count})</a>"); ?>

results this separate page template cannot display categories. If header.php is removed, it can be displayed. Why is this the case? How should I achieve the goal of multiple calls to display?