ModalPopUp and Memory Leak

I don't see this issue. Using the sample athttp://ajax.asp.net/ajaxtoolkit/ModalPopup/ModalPopup.aspx, the working set of iexplore.exe (IE7) stays steady and/or goes down with each invocation. Which browser are you using?

I am using the modal popup extender and I also notice each instance taking a minimum of 10-15 MB. The memory is not released until the browser is refreshed. Why is it consuming so much memory? Thx.