RT-Extension-UserDetails not working with IE8

I really like this extension, which allows you to view user Details by
clicking on a button beside the “people” in a ticket.
I am testing against RT 3.8.4, ad have applied the patch mentioned in the
All was working well until tested on IE8.works for Firefox and Safari, but
not IE8 (not sure about previous IE versions).
I don’t use IE myself, but other user will.

Problem: The button doesn’t show up.

The source looks ok:

<a href="/rt3/Helpers/Toggle/UserDetails?id=22" onclick="ahah('/rt3/Helpers/Toggle/UserDetails?id=22&Toggle=1', 'toggleuserdetails-22'); return false;"

Anyone have a fix or work-around?