I'm using SW Pro 2019 SP 3.0.
See the following two forms of the same constrained sketch. If the sketch is fully constrained, I shouldn't be able to grab anything and move it. I was adding constraints and I got to the first form but realized the rads were way too big, but noticed that the whole sketch was black. When I exit the sketch, the [-] disappeared from the "Sketch1" object. Yet if I grab the 45 I can move it to make the rads bigger and smaller.