New skillshots before dying
Does the game register the fact that you did a new skillshot before getting killed and reverted to the last checkpoint? I'm afraid it doesn't, but wanted to make sure.
Yesterday, I did one, got killed and checked the list after respawning: there was no green check next to it, but oddly enough it was highlighted (as opposed to highlighted AND checked).
Once you perform a skillshot and then reach a checkpoint (without dying in between) then you get a check by the skillshot in the list. It's possible that the highlight occurs if you perform the skillshot at all, whether or not you ended up dying. It should be obvious, I suppose, that when you die you end up losing the skill points you accrued by performing skillshots since the last checkpoint; I'm pretty sure the same logic follows for the checks by skillshots in the list.
It becomes highlighted because you've "discovered" the SkillShot. It gets a green check when you've gotten the points for performing it the first time. When you restart from a checkpoint, you lose the points you've gotten since you first passed the checkpoint so the green check mark goes away. However, the game still recognizes that you've discovered the Skillshot before so it remains highlighted.