Is the door lock switch on a Mercedez 300SD supposed to lock and unlock all doors?

The driver's side lock unlocks and locks the other doors, gas panel, and trunk, depending on how you have set the trunk lock. If you have one you can figure out the trunk if your system is working. There are two settings.

You can NOT lock the driver's side door if the door is open. This is to prevent you from locking your key inside.