Well if you prefer to attach it completely to the scene then correctly as a FadeSceneFragment. That way it autofades as well - thought a Scene can have different displaystates and sometimes you want to show your Window only in a specific case - if its hardlinked it will always show when that Scene is shown and there is no way to hide it yourself as it will always be faded in/out automatically in that case. To get the best of both worlds what I do in FastReport is add a virtual TopWindow that 's empty as a SceneFragment and use SetParent on it with my real Window. That way I can then check if my Addon triggered the Event and set it to hidden true/false in OnStateChange - and only in that specific case. Thought right now, Im not quite sure if it inherits the Alpha correctly (I'll check that out later).
Edit: F@cking WoT. Sorry I'm writing from my Phone right
