I just started using the new GUI and I was wondering what was better-- Nesting canvases, or nesting Empty GOs (with the RectTransform). I read that you can nest canvases, even on non-UI GameObjects, but for some reason events don’t register if I go further than 2-deep on a UI nest which prompted the change.
Typical use case for nesting Canvas is to reduce the overhead of rebuilding the UI mesh after an ui element is changed.
If you change any element’s transform or scale and so on, will trigger a whole mesh rebuild for the whole canvas, which costs time. So if your canvas contains frequent changing element, it would be better to nest it in a canvas which has minimal elements to reduce the overhead.