[NTG-context] MP & \letterpercent

Hello, why the MP code doesn't draw "%" and "#" when it uses TeX's \U - inside MP block?: ---- \def\T{TTT} \def\U{UUU \letterpercent\letterhash} \starttext \letterpercent \letterhash \par \startMPcode draw btex AAA etex; draw textext("\T"); % draw btex \T etex; % Err draw btex \T{} etex; % OK draw textext("\U") shifted (2cm, 0); % Should draw "%" and "#" now - where is it? \stopMPcode \stoptext ---- TIA for explanation. Best regards, Lukas