Drop-menu effect

If any one has a chance to check out this site.
Upon entering the site there is a menu to the left with drop menus on the “about” and “portfolio” buttons. When clicked, the drop menus push the other buttons out of the way respectively with smooth movement. If anyone can help point me in the right direction as to how to acheive an effect such as this? I checked the tutorial on this site about drop menus. Would there be parts of that tut I can use for that effect? Im guessing there would be some “if” AS to be used. Im still polishing my AS skills. Any guidance is greatly appreciated.

that was it. It works great! Thanks.
Now if I only understood y the code works.