为什么JavaFX TextField listener不工作？

import javafx.application.Application;
import javafx.application.Platform;
import javafx.scene.Scene;
import javafx.scene.control.TextField;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class TextFieldListenerExample extends Application {
    @Override
    public void start(Stage primaryStage) {
        TextField textField = new TextField();
        textField.textProperty().addListener((observable, oldValue, newValue) -> {
            System.out.println("Text changed from " + oldValue + " to " + newValue);
        });

        VBox root = new VBox(textField);
        Scene scene = new Scene(root, 300, 200);

        primaryStage.setTitle("TextField Listener Example");
        primaryStage.setScene(scene);
        primaryStage.show();

        // Ensure the TextField gets focus
        Platform.runLater(() -> textField.requestFocus());
    }

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