To view the original and result animation when editing curves
A gray curve representing the current curve appears in the graph view.
You can customize the default Buffer Curve and Buffer Curve key colors in the Preferences menu Color Settings (Available only with the Modern Graph Editor.)
You can also pin channels so that their curves always display in the graph view, regardless of what is selected.
To pin and unpin channels in the graph view
See also Pin Channel and Unpin Channel.