[NTG-context] \groupedcommand missing bracket

Hi, does someone know what's going wrong here? \definestartstop[Literature] [before={\startcolumns[n=1]},after={\stopcolumns}] \define\Colorit% {\groupedcommand{\color[blue]\em}\/} \starttext This works: test \Colorit{color} text. This dont't: \startLiterature test \Colorit{color} text. \stopLiterature Why? \stoptext This gives: ! Missing } inserted. <inserted text> } <to be read again> \endgroup \stopLiterature ->\dostopattributes \egroup \getvalue {\??be Literature\c!af... l.18 \stopLiterature ? Steffen