Sandbox controls disappeared after co-op in map

[Clynnstra]

I had a map that I was working on that I wanted to show a friend. We played on it together last night and I noticed that the controls switched to "normal game" controls instead of the sandbox controls, which I figured would happen in co-op. However, I went back today and it's still in the regular game controls. I have designs started that need the old sandbox controls to be able to finish. Is this something others have experienced? Is there a setting I missed that I can go back to the previous method of designing?

[Braveheart]

'Play mode' gives you the same tools and gameplay as Story mode, 'Edit Property' gives you full access to everything