Help! My driver door stopped locking with both the remote and interior lock button unless I manually push it in while in the car and door closed. Of course the it won't lock manually if door is open and exiting the car.

 

I have had this problem on my 2004 xj v8 and traced it to the microswitch in the actuator.I don't know if the same switch is used in the XF but I was unable to obtain the switch itself.
You can buy a new actuator (expensive), an used actuator ( even cheaper) or I found that some used ford actuators (really cheap) have the same microswitch which you can cut out and solder into your actuator.