Prevent slow script errors on slow modals

I'm having an issue in Internet Explorer 8 loading a ctools modal (for editing a file via media module). The modal response is somewhat slow, and then the attachBehaviors that follows is even slower. Between the two it causes the browser to give the "A script on this page is causing Internet Explorer to run slowly" error.

The reason for the performance problems are unrelated to ctools modal. However, I was able to improve the situation greatly by starting a new thread before the modal does attachBehaviors. This way the modal loads without behaviors attached within it, and then attaches them, allowing the user to use the modal faster. Although most sites won't have the slow javascript IE8 nightmare that this site has, I think the change may be a noticeable performance improvement on many sites.