When using a shape tool, a black background appears. How do I fix this?

I am learning Vectornator for the first time and trying lesson 1 as seen here: Vectornator Academy. I am at minute 6:52 and every time I draw a shape a black circle appears. How do I fix this?

Never mind, I discovered it was because the color stroke was selected. I must have mistakenly turned it on after turning it off.