When working on getting multiple ICEfaces portlets running on a page (although this issue could apply to multiple "includes" as well), there was a problem with AJAX push updates. The format of the updates looks like this:

<updates><update address="_id19:_id20-2-0"><![CDATA[<td id="_id19:_id20-2-0">Fri, 15:21:20</td>]]></update><update address="_id19:_id20-2-1"><![CDATA[<td id="_id19:_id20-2-1">Fri, 15:21:20</td>]]></update></updates><updates><update address="_id19:_id20-2-0"><![CDATA[<td id="_id19:_id20-2-0">Fri, 15:21:20</td>]]></update><update address="_id19:_id20-2-1"><![CDATA[<td id="_id19:_id20-2-1">Fri, 15:21:20</td>]]></update></updates>

It's hard to spot on first glance but this is invalid XML as it has two root elements ( <update></update> ). This causes the browsers parser to be unhappy and the updates cannot be applied to the views. Each browser handles invalid XML in different ways so the behaviour is dependent on the browser's implementation. Safari seems to accept the first updates document and throw away the second. Firefox balks completely. I did not try IE.