Recouple Ranges resizes the range bar so that the beginning and end of the range matches the first and last keys in the track. This is useful to quickly realign the range with the keys after editing.
Recouple Ranges: Resize the range bar to fit the first and last key of the selected track.
The range bars for the selected tracks are positioned to match up with the first and last keys in their track.
Using the Position Ranges mode in Track View allows you to decouple the range bar from the animation keys. Recouple Ranges is a quick way to realign the range bars.