I'd like to push a bug that I and several others have experienced and reported already, mostly because it desperately needs a hotfix.
Right now, a terrain is targeted with an obnoxious purple hue overlaying it if you try to shape or paint it. This makes terrain work quite a headache, particularly if you intend to design terrain with great care and detail.
I hope this is not an intended feature, or if so I'd like to ask for an additional setting to disable visual overlay indicators entirely.
Meanwhile, happy holidays!
