How do I mix graphic sets in new editor?

[bulletride]

I read you can mix the graphic sets in the new editor but I can't figure out how. I feel like the Dirt set and the trees from the Rock set would work so well together I need to try this out!

[Nepster]

Change the style in the Level Properties window. Contrary to old versions, this does no longer change all existing terrain pieces and objects to the corresponding ones in the new style, but keeps them as they are and allows you to select new pieces in the newly selected style.