Snow Leopard feature - Window Resizing?

Hey guys

I was searching YouTube for Snow Leopard stuff (I was really bored) and I came across this video showing a new animation supposedly from Mac OS X Snow Leopard?

http://www.youtube.com/watch?v=0zII-4aLr0I

Does anyone know if it's real or just complete BS?

I'm guessing it's BS because I haven't heard anyone else talk about it but I'm not 100%