Why doesnt the keyless entry button unlock all 4 doors on a 2004 mazda 3?

[paradoxisinteresting]

The keyfob will lock all 4 doors, but it only unlocks the drivers door....and then at that point the power lock button wont open any of other 3 doors either and you have to manually reach inside the car and unlock each door one at a time.....any clue as to what might be causing this??................also, it might be relevant (or maybe not) that today when was parking it it was beeping and indicating that the key was still in the ignition (which is was not)..and then the drivers door would not lock at all............is something wrong with the computer somehow? help i need to fix this so my kids and i can safely exit and enter the car without fighting with the locks...any advice?
yes opening the drivers door only IS a safety feature, BUT all 4 doors are supposed to unlock once you push the keyfob button twice....or at least hit the 'unlock' button on the inside of the drivers door....but it doesnt
no its not aftermarket, and used to work properly (i just got this car off a friend)

 

[dc]

sometimes, not always.... pressing it once will unlock driver's door, pressing it twice unlocks all doors.
If it's aftermarket keyless, then it may only be wired to the driver's door.

 

[VickyS]

It will only unlock the drivers door as a safety feature, in order for, for instance, a single woman to reach her car safely, unlock and get in swiftly without the possibility of anyone being able to get in another door at the same time. Useful, and a thoughtful feature I have to say! As for the beeping problem, that may be a warning of a low battery in the key itself rather than any fault with the wiring of the car.