[NTG-context] background color problem

I try to create some text with background color. The following code snippet doesn't work however. ___________________________________________ \definecolor [darkgreen] [r=.0, g=.5, b=.0] \setupcolors[state=start] \starttext \startbackground \setupbackgrounds [text][text] [background=color, backgroundcolor=darkgreen, backgroundoffset=1.25mm] Background color should be darkgreen \stopbackground \stoptext ___________________________________________ I know that the problem might be sitting in front of the monitor. So, where am I wrong? Manfred