iconifiedProperty is not updated when application window is minimized (by clicking on minimize button in right upper corner on ubuntu 12.04 LTS)

public class Main extends Application {

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(final Stage primaryStage) {
        primaryStage.setTitle("Popup Example");
        primaryStage.setWidth(300);
        primaryStage.setHeight(200);

        primaryStage.iconifiedProperty().addListener(new ChangeListener<Boolean>() {

            @Override
            public void changed(ObservableValue<? extends Boolean> observableValue, Boolean oldValue, Boolean newValue) {
                System.err.println("Iconified changed to " + newValue);
            }
        });

        HBox layout = new HBox(10);
        primaryStage.setScene(new Scene(layout));
        primaryStage.show();
    }
}