"Match shape - in place" option for slices

[Zoltán]

I would like to see a right click option for slices
"Match Output shape In place"
"Match Input shape In place"
This would match the shape of the slice, but would leave it at its current position.

I am mapping currently to a triplehead 2x1024x768 from a 1x1024x768 composition, and every time I use the match Output shape for slices on the right side of the output, the input slices go out of the visible area.