As someone who is not using your project, I went rummaging through the git so I could quickly write out TooltipSpawer, from what I can see it uses MonoBehaviour, IPointerEnterHandler, IPointerExitHandler.
Where do IPointerEnterHandler, IPointerExitHandler come from? Are they something that you guys wrote and what file are they in? Or do I need to just add a “using” like UnityEngine.EventSystem?
All the best
Will