When using compare mode - the current ability to "unlink" and scrub one clip would be greatly augmented by the ability to synchronize to the chosen frame when you "relink".
Often times media you want to compare is out of sync with slightly different start frames, etc. Currently to utilize compare mode, it appears both clips need identical start frames.
Alternatively (or in addition to), if compare mode respected the user specified "In Frame" that would be helpful to synchronize.