I'm using a small CMS for a small site (http://www.ovlu.li/cms/). There I include a JavaScript on the first site to open an image in a popup:

<script type="text/javascript">
function pop(file)
{
helpwindow = window.open(file, "Vaterland", "width=600, height=796",  "directories=no", "toolbar=no", "location=no", "status=no", "menubar=no", "resizable=no");
helpwindow.focus();
return false;
}
</script>

This works fine in FireFox, Chrome and Safari, but unfortunately, in Internet Explorer this script totally destroys the layout of the site where it is contained. Nevertheless it works. And all other sites are also working correctly. Any hints?