Hi, under heavy load with several threads we get following:
JavaFX Application Thread <--- Frozen for at least 57s
com.sun.glass.ui.gtk.GtkApplication._runLoop(Runnable, boolean)
com.sun.glass.ui.gtk.GtkApplication.access$200(GtkApplication, Runnable, boolean)
com.sun.glass.ui.gtk.GtkApplication$5$1.run()
java.lang.Thread.run()


in many conditions the application will run along but sometimes it stops. We developing a RCP framework where many threads are calling Platform.runLater ... on windows and mac osx it runs well but on linux we get this freeze in com.sun.glass.ui.gtl.GtkApplication.

I created a simple (but extreme) example where this error occurs most of the time:

public class HelloAsyncRunLaterSlow extends Application {
    @Override public void start(Stage primaryStage) throws Exception {
        System.err.println("Application.start");

        final Button startButton = new Button("Start");
        final HBox box = new HBox();
        box.setMinHeight(600);
        box.setMinWidth(800);
        box.setCache(true);
        box.getChildren().addAll(startButton);
        startButton.setOnAction(new EventHandler<ActionEvent>() {
            @Override public void handle(ActionEvent event) {
                createThread(box).start();
                createThread(box).start();
                createThread(box).start();
                createThread(box).start();
                createThread(box).start();
                createThread(box).start();
                createThread(box).start();
                createThread(box).start();
                createThread(box).start();
                createThread(box).start();
                createThread(box).start();
                createThread(box).start();
                createThread(box).start();
                createThread(box).start();
                createThread(box).start();
                createThread(box).start();
            }
        });

        Scene scene = new Scene(box);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private Thread createThread(final HBox box) {
        return new Thread(()->{
            for(int i=0;i<100000;i++) {
                final int counter =i;
                try {
                    Thread.sleep(10);
                } catch (InterruptedException e) {
                    e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
                }
                Platform.runLater(()->{

                    box.setCacheHint(CacheHint.SPEED);
                    box.getChildren().clear();
                    box.getChildren().add(new Button("counter: "+counter+" in Thread:"+Thread.currentThread()));
                    box.setCacheHint(CacheHint.QUALITY);
                }) ;

            }

        });
    }

    @Override public void stop() throws Exception {
        System.err.println("Application.stop");
    }

    public static void main(String[] args) {
        Application.launch(args);
        System.err.println("return from main method");
    }

}