CE did'nt respond to the steel walls

[RAP]

When I was making a new mini-game, I recently discovered that the CE
touching the steel wall did'nt change (explode at my mini-game); so if I put
a normal steel wall near to it, it will change; the problem within the bug is
the oustide boarder of the steel walls (AKA level size)...

[Daniel H.]

The steel walls that make up the outside of the level are a different element than genuine steel wall.

To work around this, make your own steel wall border that hides the default border.

[Zomis]

Daniel H is quite right here.
However, the techniqual reason behind this is that the steel wall border is not placed on the map. But it's still a normal steel wall element. And custom elements does not make any reaction caused by elements which are not placed on the map.