These commands either
hide or show function curves that are not selected in the controller
When Hide Non-Selected
Curves is on (the default), the curve will disappear when another
track is chosen.
When Show Non-Selected
Curves is on, the curve will still be visible in the Key window
when another track is chosen.
If you turn on Show Non-Selected
Curves, then you can also use Freeze Non-Selected Curves. This allows
you to see the other curve but not edit it inadvertently.