As delivered the touch sensor is configured for opening drivers door only. This makes sense when you consider your wife opening the door in a dark parking lot, you don't want the bad guys on the ground on the far side gaining entry. You change that in the MMi.On the car option you can set it up so it unlocks all the doors, I only hace to Touch the front handle (no need to open the door) and all 4 door get unlocked.
Also, on locking with the sensor, all open windows and the roof are closed if you hold the sensor for a few seconds. At least in Canada mine does. This came standard from Audi.