Updated solution
Two characters have double jump and two have glide. In order from left to right at the bottom of your screen they are Double Jump, Glide, Glide, Double Jump. Swap to the second or third character and hold your jump to glide off the highest point in any map and just glide all the way to one side and back then back to the other and you should get this pretty easily.
Previous solution:
What I did, which may not end up working for anybody, was wall jumped and began gliding away from the wall and then back to it, into a wall jump, and then glided again and it unlocked for me that way.