Apple Final Cut Express HD - Manual (Page 400)

400 Part VI Rough Editing
This also works with multiple instances of clips from the same media file on disk. For
example, suppose you have three items in your sequence, all from different parts of the
same media file.
If you move the audio item to the left, so that it overlaps the first video item, out-of-sync
indicators appear. The same happens if you move the audio item to the right.
What if you move all three items so that they overlap, but all are out of sync with one
another? The first two items show out-of-sync indicators relative to one another, and
the third item shows an out-of-sync indicator relative to the item it overlaps.