Thank you for the suggestions, Julie. After some experimenting, we found the following approach to be almost what we needed.

1. Select any column in Gantt view (indicator column is least intrusive to us)
2. Window, Split
3. Click anywhere in lower window
4. View, Gantt Chart

Notes:
1. Each window can be scrolled independent of the other.
2. As long as one column is selected in the upper window, all rows appear in lower one.
3. Changes made in either window are reflected in the other.

Hope others find this useful.