How do I activate and deactivate the Child Lock function?

To activate Child Lock, press and hold both the Temp. and Spin buttons simultaneously for 3 seconds. When activated, the door locks and the 'Child Lock' lamp illuminates. To deactivate, press and hold both buttons again for approximately 3 seconds, which unlocks the door and turns off the 'Child Lock' indicator. The Child Lock setting will be kept even after restarting the machine.