[NTG-context] Two questions about sort lists

Hi! I have two questions about sort lists. 1) Is there a way to reset (empty) the sorting list, to reuse it several times? \definesorting[song][songs] \unexpanded\def\SongEntry#1#2#3% {#2 \crlf} \starttext \startlinenumbering \startlines \setupinterlinespace[big] \song{Sway} \song{Hit The Road Jack} \song{Fly Me To The Moon} \placelistofsongs[criterium=all,command=\SongEntry] % (Here I want to reset the list) \song{Girl From Ipanema} \placelistofsongs[criterium=all,command=\SongEntry] \stoplines \stoplinenumbering \stoptext 2) Why any formatting tags like \song{\it Fly Me To The Moon} cause the error? Regards, Vyatcheslav Yatskovsky