So I'm not on the latest version, but I use the following technique for having child objects:
- Disable the automatic layer changing on both the parent and child object (I think the latest version does this for you. I had to manually add this feature to the InteractionBehaviour script)
- Manually disable collisions using Physics.IgnoreCollision between the parent and child objects. If your object starts spinning wildly out of control, it is because this wasn't done, and the child object's collision is pushing the parent object, which is causing the child object to move. Then on the next frame the process repeats.
After that it seems to work just fine. I've got sliders that are children of a regular old InteractionBehaviour.