Section Tools Fill Colour Control

I haven’t been able to figure out what sets this. By display and By object seems clear enough (though By Display seems to give me either the selection colour (yellow, which I don’t want) or black (which I do want), and I can’t determine what’s controlling that, as all other settings seem equal between them. I seem to be able to control it through the layer colour in some cases, but not others, despite the settings being apparently the same.