1987 300SDL Alarm Problems

Ok, well firstly, thanks for taking the time to read this.

My problem is basically as follows: Sporadically I will unlock the car from the drivers door, with the master key, open the door (after waiting a few seconds for ALL the doors to unlock) and the alarm will sound. It goes off (usually) when I close the door, lock and unlock it. Also, a few months ago I was playing with it, and realized that with the window rolled down, I could pull up the door lock shaft, unlock all the doors, and the alarm wouldn't sound. (Only when done from drivers door (I was wondering if maybe there was a connection)) Is it just the switch in the door that detects when the door is opened?

Thanks very much!
-James