ScreenFlow replaces the set of nested clips with a single clip the length of the now-nested clips on the timeline.You can also nest clips recursively. That is, you can create a nest of clips, then open that nested clip and select some clips inside it and nest them, and so on. You can also go the other direction and nest two nests together, or create a nest from a nest and a clip. Although the depth of nesting is limited to ten, two or three levels is usually sufficient.