Terrain Painter doesn't do anything?

For some reason when I'm in World Editor, my terrain painter does nothing. Any by nothing, I do mean nothing. No matter what texture I choose, no matter what map I'm on, no matter how hard I press my left mouse button, it doesn't do anything. I thought it could be because my game was paused, but it isn't. I thought maybe the circle brush was broken, but the square brush also doesn't work. I'm stumped.

Thanks in advance
--- Post updated ---
I looked through an old post and realised my slope minimum was at 40 for some reason. All fixed now

 

can you please change the title to have the solved tag.