Idea: Scroll-wheel directory traversing

Holding the mouse over a folder and scrolling the wheel forward will go into that folder. Scrolling back will always go out of the current folder, up the folder hierarchy. Scrolling into a file will bring up a preview or details (depending on file type). When going in and out of folders, it will have an zoom in with alpha fade type effect, fading out the current level, and fading in the next level.