ICON set for JavaFX application is visible in Wind

It is a bit weird or maybe there is something wrong with my code.

I am setting JavaFX application ICON which is very well visible on Windows system but not on Ubuntu.

On Windows:

On Ubuntu:

Any idea about the reason behind this.

Code Sample:

@Override
public void start(Stage stage) throws Exception {

    try {
        setUserAgentStylesheet(STYLESHEET_MODENA);
        FXMLLoader loader = new FXMLLoader();
        Parent root = (Parent) loader.load(getClass().getResourceAsStream("ui/ParentWindow.fxml"));
        final ParentWindowController controller = (ParentWindowController) loader.getController();

        stage.addEventHandler(WindowEvent.WINDOW_SHOWN, controller::handleWindowShownEvent);
        stage.addEventHandler(WindowEvent.WINDOW_SHOWING, controller::handleWindowShowingEvent);
        stage.addEventHandler(WindowEvent.WINDOW_CLOSE_REQUEST, controller::handleWindowClosingRequestedEvent);

        Scene scene = new Scene(root);

        scene.getStylesheets().setAll(
                getClass().getResource("ui/css/ParentWindow.css").toExternalForm()
        );

        stage.setScene(scene);
        stage.initStyle(StageStyle.UNIFIED);
        stage.setResizable(false);
        stage.toFront();
        stage.setTitle("Simple JavaFX Tool");
        stage.getIcons().add(new Image(getClass().getResourceAsStream("resources/images/icon.jpg")));
        stage.show();
    } catch (IOException iOException) {
        iOException.printStackTrace();
    }
}

For people looking for solution, this is an open issue in the JDK issue tracker.

Gtk: Implement global system menu bar support

According to a comment by JavaFX developer on a similar issue :

Glass/FX currently doesn't support the global menu bar on GTK (RT-28202). As such, Glass doesn't set any application-wide hints to specify the application name or application icon. The desktop environment has to guess them itself (likely, using a window's title and icon). Hence, it is correct that the "app window" (#1 above) should always display the correct title, while the other 3 places may or may not display the correct title depending on timings. This is unlikely to change until RT-28202 is implemented.

RT-28202 was the issue id for the above linked issue before JavaFX issues was merged with JDK issues.

This issue has a very less no of votes and therefore hasn't attracted much interest. If you are registered as a contributor, feel free to vote for the issue.