The PlayerMouseButtonEvent and PlayerMouseMotionEvent are currently not firing due to an internal Hytale engine error. A fix is scheduled for the next version of the game (patch 2026-01-17).
Additionally, the SwitchActiveSlotEvent is also affected by an internal error and is not firing. I am still awaiting confirmation from other devs, though it may potentially be included in the same patch (2026-01-17).