Main toolbar > Curve Editor (Open) > Right-click the starting area of a toolbar (containing two vertical bars). > Choose Show Toolbars > Ranges : Dope Sheet.

This toolbar, hidden by default, provides tools you use when working with ranges.

Edit Ranges—Changes Dope Sheet to display range bars rather than tracks of keys. See Edit Ranges.

Position Ranges—Adjusts the relationship between a range bar and its keys. Turning this on will allow you to see the keys while moving the range bar.

Recouple Ranges—Resizes the range bar to fit the first and last key of the selected track.