When explicit in and out points are not set, you can have phantom marks appear either on the source clip or on the timeline.
Phantom marks on the timeline indicate the result of an overwrite edit before the edit is performed. Phantom marks in the source clip indicate the material that will be used for an overwrite edit.
For example, if your source clip has both an in and out point, and the currently selected record clip has an in point, a phantom out point appears on the timeline. If you change the in point of the source, the phantom out point updates to reflect the same duration as the source duration between in and out points.
Phantom marks appear as a light pink bracket.
To enable phantom marks: