[Daniel]

For anyone looking to make their showgroups.php page collapsable...

Go to template showgroups_usergroup and replace it completely with:

<div class="block collapse">
<li class="block usergroup" id="group{vb:raw xhtml_id}">
    <h2 class="blockhead">{vb:raw user.title}
<a class="collapse" id="collapse_{vb:raw user.title}" href="{vb:raw relpath}#top"><img src="{vb:stylevar imgdir_button}/collapse{vb:raw vbcollapse.collapseimg_cel_dummy_img}_40b.png" alt="{vb:rawphrase collapse_this_category}" /></a></h2>
    <ol class="blockbody" id="{vb:raw user.title}">
        {vb:raw usergroupbits}
    </ol>
        
</li>
</div>

Collapsed as default? Yes, replace

<ol class="blockbody" id="{vb:raw user.title}">

with

<ol class="blockbody" id="{vb:raw user.title}" style="display: none;">

Thanks to cellarius for the original post.