Studio: Onion skinning not visible while rotoscoping.

When I import a video as a layer and try to paint over it frame by frame, onion skinning doesn’t seem to work. Any ideas what I’m doing wrong? Thanks!

Move the selected Video Layer slightly backwards…
Either manually, or alt+uparrow, or open the Properties-panel and type 0.01 B
into the third Offset window and hit return or enter…