How to find what ActiveX control is referred on a web page?

I have developed a web app开发者_Go百科lication (ASP.NET Web Forms). One of my customer has very restrictive policies. When he accesses the web page, IE shows this message:

Your security settings do not allow Web sites to use ActiveX controls installed on your computer. This page may not display correctly.

As far as I know, we don't use ActiveX controls on our page. I did a "View > Souce" and did not find anything suspect.

How can I find what part of my page refers to an ActiveX. The application uses jQuery and a few jQuery plug-ins. Is there a tool/add-in like "Fire Bug" that I can use to list the ActiveX controls referred on a page?

We found out that jquery causes this on IE6 with our customer's security policies. The workaround was to add our web site to the trusted sites.