When you first start the car you have to have you foot on the brake pedal (this you will know) this also applies to the parking brake button, once you are driving the car and say you stop and apply the brake it will release automaticity when you press the accelerator.

 

Ah, I'll try that.
Don't tell me other people apply the parking brake in traffic / at red lights?!
Our other car has auto hold, which is similar but more logical.

Plus, just saw this thread: I give up! Handbrake shenanigans... Should've searched, sorry.

 

On a downward slope you need to apply the brake otherwise the car will drift forward, on an upward slope the car will hold its position.

 

As a note, most vehicles with auto parking brake require the drivers seat belt to be engaged to enable auto release of the brake.........just in case it caught you out.

 

On my 225xe the handbrake also automatically engages and disengages on a slope once the P or D/R is respectively selected if foot still on brake

 

It's also got a hill-hold that's not using the electric motor. On steep slopes the auto hold won't stop the car rolling back (if you're pointing uphill) but if you push hard on the foot brake it'll hold the brakes on for an extra couple of seconds when you release your foot.