Hi, I have done some porting to gtk4: https://github.com/openjdk/jfx-sandbox/tree/tsayao_gtk4_playground It currently compiles, but does not show any windows (I suspect of an threading issue). Some parts such as DND are commented out. To use it, pass: -Djdk.gtk.version=4 -Djdk.gtk.verbose=true -- Thiago.