Since this would require the definition of several colors, not just one (against various backgrounds), I think it might make more sense to have an option to lower the opactiy of the default text color. What do you think?

Wow, I honestly don't remember raising this at all. I'm guessing what I was looking for was more akin to a single extra color option under the "Effect Highlight" color selection so that you could color commands like Sxx without changing any other foreground colors (which doesn't quite line up with the issue description, but seems more useful to me reading this now...). That said, I don't think an opacity setting would be a bad idea either.

Hm, that would then color the effects, but leave note-offs etc. the same color as the empty space dots? I'm not sure if that's better, because if you want to reduce the visibility of the dots, you would also have to reduce the visibility of note-offs (and PC parameters, etc). Tricky.