Keyboard browsing the Browse Tree?

How come you can't use the arrow keys to step thru i.e diffrent playlists in the Browser Tree? Now you have to use the mouse to click on the playlist you would like to see, and then as you use the arrow key up or down, you step thru the tracks in the right area called Track List. As I use the playlist (could be the folders in the Itunes tree) I have to be able (and want to) to step thru the diffrent playlists pretty quick, this is not done with the mousepad.

Same thing in the Preferences window, really annoying that you have to click thru the diffrent preference-pages, instead of being able to use the keyboard and press up/down. It makes no sence.