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

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Edit Ranges
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Changes Dope Sheet to display range bars rather than tracks of keys. See Edit Ranges.
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Position Ranges
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Adjusts the relationship between a range bar and its keys. With this option on, you can see the keys while moving the range bar.
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Recouple Ranges
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Resizes the range bar to fit the first and last key of the selected track.