Hiding Sublayers

Loving the new layer system! My only gripe (and maybe I'm just missing how to do it) is that I can't find a way to toggle visibility on sublayers.

For me this is important because I like to have various things on the map that I can show my players depending on the circumstances (dead bodies, gas clouds, black overlays to hide rooms, etc.). I can work around this by putting each set of things to reveal on its own layer, but this seems inefficient and harder to manage.