Current Menu Item not working with $childpages
<p>I need to add the "active" or "current-menu-item" class to a custom childpages menu. I've tried the code below but it doesn't seem to work.</p>

<p>I've browsed google but can't find anything that will work!</p>

<pre><code>&lt;?php
$childpages = query_posts('orderby=menu_order&amp;order=asc&amp;post_type=page&amp;post_parent=35&amp;posts_per_page=300');
if ($childpages)
{
    // Display the children content
    foreach ($childpages as $post)
    {
        setup_postdata($post)
        ?&gt;
        &lt;a href="&lt;?php the_permalink(); ?&gt;" title="&lt;?php the_title(); ?&gt;" class="mezzanine-sub-title &lt;?php echo!empty($_GET['page_id']) &amp;&amp; $_GET['page_id'] == $post-&gt;ID ? "active" : NULL ?&gt;"&gt;
            &lt;span&gt;&lt;?php the_title(); ?&gt;&lt;/span&gt;
            &lt;a&gt;
                &lt;?php
                global $post;
                $src = wp_get_attachment_image_src(get_post_thumbnail_id($post-&gt;ID), array(5600, 1000), false, '');
                ?&gt;
                &lt;div class="mezzanine-sub-image" style="background: url(&lt;?php echo $src[0]; ?&gt; );border:&lt;?php the_field('border'); ?&gt;;"&gt;
                &lt;/div&gt;
            &lt;/a&gt;
        &lt;/a&gt;
        &lt;?php
    }
}
?&gt;
</code></pre>

<p>Thanks in advance</p>