Am 23.05.2014 um 01:09 schrieb Maggyero <maggyero@gmail.com>:

Thank you Wolfgang, your hack is perfect. Hans, what do you think about adding a style and color key in \setupreferencestructureprefix to avoid having to use this defineprocessor hack?

The processor command is meant for this purpose to apply to a apply a different format for certain counters etc.

And by the way, the name \setupreferencestructureprefix does not sound really natural to me because we are talking about a reference NUMBER and there is not always a prefix. What about changing it to something like \setupreference or \setupreferencenumber (like \setuppagenumber)?

I agree that the name itself isn’t very good but you have to know that section numbers are considered as prefixes when they appear in front of the figure, table etc. counters.