@javafxpert It might be easiest to go from your program -> Kotlin/JavaFX -> TornadoFX. I see you’re using IntelliJ, so the IDE might automatically convert a lot of your program to Kotlin for you.
From there, the refactor to TornadoFX would be very easy and I think a lot like the days of JavaFX script or visage. You’ll create an App / View pair and use Type Safe builders to build you the UI (ex “region{}“).