at a certain speed ONLY the passenger side will fold in, then if you got a bit slower, both fold in.
just play with it to see. its very slow speeds. handy feature.
you do NOT need to be stopped to ahve them both fold in, but you're damn near it speed wise.

OT, but I realize I have a micro switch available if you need it. I removed it out of my former mirror assembly

Replaced my DS with a brand new mirror, as the gears were bad and there was slight slop/play in the mirror.

Repaired my mirrors by reforming the arm on the microswitch. I had gotten jammed and was causing the fold in, then immediately back out issue. Works great now. There is a great thread on it here.

As an aside... both my mirrors fold in at virtually any speed and in any gear. Maybe it's programmable in the GM?

INTeresting. Maybe post facelist versus prefacelift.

Pre - I would say the cutoff is somewhere around 8-10mph.
Mine is not speed dependant per the previous post on passenger or drivers/passenger. It will do both, as long as you're in the cutoff speed --- I presume BMW implemented this for safety reasons

Ok focus please.:D My mirror unfolds right away even when engine is at off.

I just need an instruction on how to pop off the mirror cover without breaking anything . I tried to do it very slowly like jsoto suggested but got scared thinking I may break the clips.

Are there any hand tools that may help prying it off?

Use the plastic trim tool (out of the 10 I have in my stash, I think only of those 2 wedges are thin enough) or just even a CC.

Your microswitch - either the metal prong off the switch is messed up (aka, that's why it senses to fold back out) In my case, when I removed it, the metal prong was completely missing (MIA).It's very small..think of it as a small paper clip, about 1/2-3/4" in length

You're just going to have to "nut up" as they say and yank it off slowly. Takes a decent amount of force. I use a plastic "bone" pry tool and was careful the first few times I did it... I broke a bunch of those small wedge looking things but the clips hold it on there fine when reinstalling. Subsequent removals (on 2 different X5's) I just yank it off there now with much less care since you are almost guaranteed to break the little wedge things. Clips should survive though. Mine always do.