Opening Dialog causes js error in IE7 if dialog content contains VML

This is a hard one to know where to log so I understand if you think it shouldn't be with jquery-ui although it is caught in the middle between the two libraries that I think aren't playing nicely - dd_roundies.js and jquery 1.3.x. It actually seems to be a regression from when jquery-1.3 was introduced and I believe i've narrowed it down to a particular line in jquery that is failing.

The test I have attached shows that when dd_roundies.js creates VML based rounded corners for any elements within a dialog, jquery throws an error when opening the dialog. I think this is based on the following function in jquery when 'elem' is a VML element.

Sizzle.selectors.filters.visible = function(elem){

return "hidden" !== elem.type &&

jQuery.css(elem, "display") !== "none" &&

jQuery.css(elem, "visibility") !== "hidden";

};

My VM running IE7 and debugger are playing up at the moment so i'm finding it hard to debug properly.