Problem with collision


i have a problem with collision.
I new to Hard Bodies, and do not know how to
set up the on or the other thing.

I used the Hard Bodies tutorial from

I just set up a cube and another cube which falls on the first one.
All works fine, except the collision. The box stops over the first cube.
It seems that the collision is not precise enough.

See attached png.

Is it possible to set up the precission?