Editing a clip

Edit Clip (Alt+G) opens the clip so you can draw inside it. Done Editing Clip (Alt+D) returns you to the scene. The active clip stays visible while you edit it.

Split Clip (Ctrl+Shift+G) breaks one clip into two.

Copies of a clip stay linked. Change one and the others follow. Make Unique disconnects that copy, so later edits stay on that instance only.