[Lynne]

OK, on to some more testing to figure this out. I compared your working test page with your non-working showthread page. Here are a couple of lines (some javascript codes) that get called on the non-working page. Try inserting them one by one into the working test page and see if they 'break' it:

<script type="text/javascript" src="clientscript/post_thanks.js"></script>

<script type="text/javascript" src="clientscript/vbulletin_post_loader.js?v=370rc3"></script>

<style type="text/css" id="vbulletin_showthread_css">
    <!--
    
    #links div { white-space: nowrap; }
    #links img { vertical-align: middle; }
    -->
    </style>