[NTG-context] \blackrule and margin

Dear List, i have the little following example: \setuppapersize[A8,landscape] \setuplayout[leftmargin=2.5cm, leftmargindistance=0.2cm, backspace=2.9cm, width=4cm] \showframe \starttext \blackrule \margintext{Me} \blackrule[color=black, height=0.5ex, width=1cm] \stoptext \startformula a^n + b^n = c^n. \stopformula \stoptext What i want is a\blackrule over the margintext, but i do not get what I wantend. Uschi