I just picked up a 328 vert with comfort/convenient access. When I park, press the button to stop the engine, and then exit the car, the sound system stays on and the iDrive screen stays on. It will shut off if I touch the door handle and lock the car, but stays on if I don't lock the car. It does shut off eventually, but I don't understand why it doesn't shut off right away. Can anyone shed some light on this? By the way, this is my first ever post on a forum. Hope I haven't embarassed myself!