I am experiencing issues when porting a JavaFX application from version 17 to 21. Specifically, I’m having trouble setting the location of a Stage. I am using openJDK from https://adoptium.net/, javafx-sdk and javafx-jmods from https://gluonhq.com/products/javafx/. To better illustrate this issue, I’ve created a simple example:

import javafx.application.Application;
//import javafx.stage.Modality;
import javafx.stage.Stage;

public class App extends Application {
    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage primaryStage) {
          Stage stage = new Stage();
        //stage.initModality(Modality.APPLICATION_MODAL);
        //stage.initModality(Modality.WINDOW_MODAL);
        //stage.initModality(Modality.NONE);
        stage.initOwner(primaryStage);
        stage.setTitle("Test App");

        stage.setX(500);
        stage.setY(500);
        stage.setWidth(200);
        stage.setHeight(100);

        stage.showAndWait();
    }
}

While javaSDK/javaFX versions 11 and 17 work correctly for me, version 21.0.5 on Ubuntu 24.04 (which also works fine on Windows 11) sets the window to location (0,0) in 8 out of 10 times.

Any advise?

p.s. I am not running on Wayland.