It can be useful to have visual reference points on the timeline to help you position edits relative to other tracks. For example in manual synchronization of audio and video. You can set two points on the timeline with In/Out points or by selecting a range in Cut and Paste mode. Now we use Settings → Loop Playback (Shift - L) to make two vertical green lines appear at the edges of the selection. Originally this function is used to limit the playback within this range, but we can take advantage of the fact that the green lines remain even when we move the insertion point or delete the In/Out points or deselect the range. So they can be used as a visual reference when we want to move the edits precisely. To delete these guides press Shift-L again.
The CINELERRA-GG Community, 2021