F18BEN

Most cars unlock only the drivers door when you press the unlock on your remote. All Mercedes default to open all doors with one click. To correct this do the following.
Press the lock and unlock button simultaneously for 7 seconds on your key FOB. The remote red light will flash twice. Now one click will open the drivers door and two clicks open all doors. To reverse this just repeat the procedure. It's much safer when you are in a parking lot. I just did it on my GLK and E350.... Frank

SD90

Is there any way to just open the drivers door with keyless go?
As soon as I touch the driver's door, all doors unlock.

NYCGLK

owners manual might tell you that.

pipicyx

press unlock and lock together for 6 secs on the key
this will change the behavior between unlock dirver+gas and unlock everything.