Hallo!
Many thanks - it works !
LG Georg
I replied too quickly,
a better (more general solution which could involve more movies and
no masking) would be:set the gemwin 'orthagonal' layer the movies so A is furthest away, then B, C etc in front of this place a black rectangle then transparent rectangles part A, B C etc
render order is: movie A then part A then movie B then part B then movie C then part C etc finally render the black rectangle
this way you can easily move the part around