@edvin I have something in my repo that wasn't merged in. It's a unit test and App subclass that only seems to work if I use a JavaFX technique. This was from when we were looking at writing our own FXMLLoader. I think the problem is the nested fx:include needs a Controller but "by fxml()" might introduce a loop where the toplevel View() loads a child View() through the fx:include reference. The child View() tries to load it's own FXML as part of root