>
> ​​
> \definebar[urlbar][underbar]
>
> \setupurl[style=\mono\urlbar,color=blue]
>

​Interesting, thank you, Hans, it indeed works as expected.  Could you
supplement this with some explanations, i.e. why this one works compared to
using plain `underbar'?​  I assume that the `color' key is overridden
by `setupurl' in the case of `urlbar' but not in the case of `underbar',
why?

Regards,
Alexander