Due to User Agent Strings like: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0) - the current browser check actually matches IE9 as IE6 and, thus, the animation was not working. Performed a strong check based on using support and an XOR to determine whether the browser was IE6. This also solves the issue of $.browser not being support starting in jQuery 2.0.