Need a onRollOut when you press on another button

Im going to do a menu on the left side of my site and I want the buttons to fade when you hold over them and then fade out when you leave them and when you click on the menu I want a new window to come out. I have done this but When you leave the button the new window disappear I think I can fix this but heres the big problem:

[COLOR=Red]I want the window to go back (not only disappear at once) when you click on another button…

[COLOR=Black]But I have no idea what action script I need to use to do this… If anyone know a tutorial or can explane how to do this I would be very glad :)[/COLOR]