second attempt at patch for #1966

I encountered some trouble with my previous pull request, so I just decided to start over again.
Hopefully now I am in sync with the main repository, and everything will go smoothly.

Again, this creates a transparent radius around the object hovered over with the tearing tool. Fixes #1966.

Please excuse me if I've caused any confusion or problems, I'm pretty new to this; again, any kind of feedback would be greatly appreciated, thank you.