@edvin I think it's ok to use View-to-View calls rather than the event bus for menu navigation. I'm using find(MyView::class).openModal() in an app. Maybe something like find(MyView::class).replace() would work?
TornadoFX could use a Navigation service to help blend the replaceWith() and the opens(). This way the navigation is more flexible and can be used for menus, toolbars, keyboard shortcuts, etc.