when I built my panel (forever ago) i put in a happ trackball in for one reason Centipede.. I played it for hrs in the laundromat while my mom did the family clothes. I even helped people carry baskets in and out to their cars for quarters, lol.. but having it on the panel makes it easy to navigate windows without the KB tray out.. as a mater a fact i don't even have a proper mouse on the machine.