Steam VR2 - colliders in Interactive demo question

Hi, I’ve had Unity for a couple of weeks and have a complete beginners question.

I have installed the Steam VR 2 plug in and I am running the Interactions demo Scene that comes with the download.

I am trying to understand how objects pass through each other or not.

In the scene we have two tables, one with cubes and spheres that you can pick up and they can be passed through other colliders. The other table has cubes and spheres that can not be passed through other colliders.

In the two hierarchys the actual cube and sphere gameobjects have identical components and are no different to each other but if moved under the other parent gameobjects their behaviour then changes. A passing through cube moved under the parent of a non passing through cube had it’s behaviour changed.

So, the difference must be in the parent object?

However, I can not see any significant difference between the two parent objects that would change the collider behaviour.

The small component differences there are I have changed just in case but I’ve had no joy.

Can anyone explain in this scene why the two parent gameobjects generate the two different behaviours? In beginners speak!

I want to move this behaviour to an industrial application for moving production parts into specific areas.

Thanks in advance.

Craig.