After using Internet Explorer 9 for a week, i've noticed that there are quite a few applications that do not work well with it, one example is the CKEditor used to update this blog, another is the BlogEngine that is used on a different blog. In both cases, updating to the latest version fixed the problems.

I've been using IE9 RC1 to evaluate all our websites and fortunately not come up with any problems. In a couple of cases, updating the jquery to the latest version was all that was required to restore functionality.