Aha! I was able to solve it using this solution, sort of. Instead of selecting a shape, I had to move into the tile selector, and create a new object by selecting all of 'KO' and the top left corner of 'N' which successfully de-linked the two. I then had to carefully trim with the eraser color, or else part of the N would also be erased, but it worked, and now there are no black edges to speak of! Thanks!