Obstacle course boundary difficult to place

[microwavekonijn]

When building an obstacle course I had some issues with placing them. The first issue is that they are hard to see, I would like to seem them highlighted in a solid color. That way you can see better were you place them and were they intersect.

The second issue has to do with placing and selecting placed boundaries. Sometimes these actions don't work and I have really no clue why that is(for placing them I thought it had to do overlapping other object, but not with all objects).