I can't paint in the 2D view. Either I can move the pen over the image, and nothing happens, but the cursor moves appropriatel - or the cursor seems to be stuck in a certain spot regardless of where I move my pen (and in this case paint will appear where the cursor is stuck). Painting in the 3D view works just fine. I am able to paint in the 2D view in other projects. Changing the alignment doesn't help at all. Any ideas how to fix this? Thanks!