Dear Hans, Wolfgang,

Both of your methods are working well.

Using \frame, the \dorecurse problem is solved.

\starttext
\startanimation[menu=yes]
 \dorecurse{10}
  { \frame{\useMPgraphic[stacking={#1}]{demo}}}
\stopanimation
\stoptext

Thank you for your solutions.

Best regards,

Dalyoung