[NTG-context] loop textext and \MPstring{…}

Hi, I am trying to achieve the following: \setMPtext{1}{ABC} \setMPtext{2}{DEF} \setMPtext{3}{GHI} \starttext \startMPpage[offset=1ex,width=\paperwidth,height=\paperheight] for i=1 upto 3: draw textext(\MPstring{i}) shifted(i*cm,i*cm) ; endfor; \stopMPpage \stoptext There is no error but no content either. What's wrong? Thanks Andreas