stchur tackles an issue which has cropped up for me in the past - that mouseout and mouseover on a container element will also trigger for its children. This can be incredibly annoying, and it surprised me to find out that Internet Explorer has a built-in solution in the mouseenter and mouseleave events. These are only triggered for the container element, not for the children. However, non-IE browsers don't support this and so stchur made mouseenter and mouseleave for Firefox. Extremely useful, and I'll be using his work as inspiration for a new feature in the next TickerTape version.