Hi ZeldaVerde (love the name) I just tried a little something that might help. This 2 event setup enables double jump only when the player hits the jump input and should work even if you change the input from default to something else since it enables on jump. It disables double jump again once you land. If you walk straight off a platform you get no jump and just fall. I hope this helps!
Thanks (:! Probelm is, construct's on landed or is on floor is pretty buggy, and it loves to trigger when it really shouldn't for no reason. BTW, can you perhaps speak Portuguese or Spanish? I'm wondering because you apparently understood my name...