Iframe in wiki-rendered description hoses issue view in Jira 4.1

If I render the description of an issue as wiki markup and include an iframe to something sizable, the view of the issues cuts off after description. For example if the markup includes:

{html}<iframe src="https://whiteboard.soliantconsulting.com/display/REGN/Electroporation+Screen+Genotypes" width="1000" height="400"/>{html}

This is a view of a Confluence page – the confl page can be viewed but the rest of the issue below the description is not visible.