Hi @Isaac! I’m on mobile at the moment, but I can say it works correct in my own project. Unfortunately, I can’t find a difference with your project. Below an example project to compare your setup.
The issue is that WindowElems entity doesn’t have an element component on it. There are some UI features that rely on all parents to have an element component to work correctly.
Adding an element that is group element that is ‘full screen’, makes the masking work correctly
Maybe we could have some sort of warning indicator in the UI here? Or even a prompt for automatically adding required elements to all parents could be helpful…
I don’t believe this is a bug, but rather a requirement for the UI system to work properly with high performance. Posted my thoughts in the ticket, but basically yes, I think it makes sense to add a warning there.