[NTG-context] ! Argument of \chaptercmd has an extra }".

Dear list, There were a page setting of ConText as below, It seems be error. How can I fix it? Thanks very much! \def\chaptercmd#1#2{\hbox to \hsize{#2\hfill\switchtobodyfont[48pt]{% \color[darkgray]{#1}}\HeadOffset}} \setuphead[chapter][command=\chaptercmd,after={\blank[2cm]}] Regards Kedy