If an editing operation removes the sync for a track in an edit sync group, a red plus (+) or minus (-) symbol appears in the element and the Sync offset appears on the element.
You can either resync the elements or reset the offsets, creating a new sync relationship based on the current position of the segments.
(a) Child out of sync to the right (b) Child out of sync to the left
The element is re-synced, if possible, and the out-of-sync symbol turns to an “=” sign.
The segments remain in their current positions. The sync offsets are removed creating a new edit sync group.