Enable elevation overlay in editor while placing objects?

[Nickel Plated]

Anyway to make the elevation lines on the map stick around outside of landscaping mode in the editor?
I'm trying to place some trees in a valley and I want them to stay literally just inside the depression of the valley and leave an open plain above it. But the valley is fairly shallow and it's kind of hard to see exactly where it starts to drop off without the elevation overlay. So hard to tell exactly where the treeline should stop.

Moving the sun around casts some shadows that make it a bit easier but still not enough and it's tedious as hell.

[john.glossop]

You could put a road around the area you want "treed", tree it, and remove the road...

[Nickel Plated]

Derp. Lol, I thought about using roads to lay it out first but quickly tried it and went "It still turns off the contour lines. So still same issue." Not realizing the road tool has an option to toggle them.

So yeah, that'll work, thank you.