...Just change the BLEND mode to "Normal" instead of "Multiply".
...I really need to add some help on that screen to guide people as I'm sure it's a common confusion. ...
Yes, I sometimes wonder how many times SC users trip over this one. I had the exact same "problem" a while back when somehow the BLEND mode got changed (I have no idea how - certainly not deliberately by me). The thing is that the "fix" is a tad obscure. I'm not usually using SC every day, and am not familiar with all of its settings. Things like this are probably "user error" though, I suspect.