ScrollTrigger -- how to set a class on reverse

[LSchneiderman]

I have a trigger that works correctly scrolling forward, but not backward. Going forward, I want the navbar to change from highlighting Part 1 to highlighting Part 2 at a certain point, then to change from highlighting Part 2 to highlighting Part 1 when you scroll backward past that point. My code doesn't work for the backward scrolling part. What am I doing wrong please?

See the Pen xxYRwGX?editors=1111 by lschneiderman (@lschneiderman) on CodePen

[GreenSock]

I think you meant onLeaveBack instead of onEnterBack. And there's no point in having reverse: true (no such thing) or toggleActions (that only applies if you have an animation associated with it): 

See the Pen LYQbNdy?editors=1010 by GreenSock (@GreenSock) on CodePen

[LSchneiderman]

Thank you, @GreenSock!!