Cinelerra: When Splice and Overwrite from the Viewer window wipes target track

… or when Paste does the same. Everything in the targeted track is deleted, and replaced with the snippet, which we wanted spliced in or overwritten. But not instead of everything!

Well, this is not a bug, but a feature: This happens when there are “in” and “out” markers (or even worse: only one of them) in the editing timeline. When these are present, Cinelerra interprets these as the points to which the snippet should go. If the “in” point happened to be at the beginning of the track, all goes away.

Simple solution: Remove “in” and “out” points from the timeline (are they there because of previous rendering?)