Move Rigidbody2d along with parent object

May be I had broke something in my project, maybe some physic logic was changed, but since Unity 5.1 when I set Rigidbody2d (Player) as a child of some platform with BoxCollider (floor) and then platform moves, Rigidbody is stay on the spot and eventually slides over platform instead of staying on the floor and movind along with it.

so, my “platform” collider


and my player rigidbody


I assume the only thing changed since last time it worked properly is this new Constraints on rigidbody, but I don’t think it may cause the problem.

I’ll be really happy if you’ll help me. I need to fix this fast but already spend a day trying to locate the problem

Child objects cannot have non-kinematic rigidbodies. You must mark the player as isKinematic while it is a child of something else.