[NTG-context] hairline & rules

I want to use a colored hairline, but can't get it working and can't find anything to explain any options or parameters. I've tried \setuptextrules[rulecolor=red,color=red] \hairline or \hairline[color=red] Doesn't work this is a test \thinrule[color=red] also doesn't catch the color or does this is a test \thinrule[color=red] Can the hairline command be set to use a specific color and how? Same for the \thinrul command Thanks