jQuery dropdown menu in Internet Explorer

I saw this jQuery dropdown menu on the net and I love it a lot. It works perfectly in Firefox and all browsers except as usual Internet Explorer. In IE, it's freaking slow and annoying. How to solve this problem?

To keep things neat, please visit: http://sandbox.leigeber.com/dropdown-menu/index.html and you will see what I am talking 开发者_运维知识库about.