Height and Warp Projection box
When dropping in an alpha into the height, using Warp Projection, I always get this indented square around the projected texture. I've tried changint the hardness (doesn't work), I've got the layer modifying the height map with "Linear dodge", which should be an "add", and as you can see in the pic below, the background of the alpha texture is black, and shouldn't be adding/subtracting anything.
What am I missing? How can I get rid of the square indent?

