TextField caret error

import javafx.application.Application;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.VBox;
import javafx.scene.text.Font;
import javafx.stage.Stage;

public class test extends Application {

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

    @Override
    public void start(Stage stage) {
        Scene scene = new Scene(new Group());
        stage.setTitle("TextField Sample");
        stage.setWidth(450);
        stage.setHeight(550);

        final Label label = new Label("click here");
        final TextField temp = new TextField();
        label.setOnMouseClicked(new EventHandler<MouseEvent>() {

            @Override
            public void handle(MouseEvent arg0) {
                //I put the text
                temp.setText("this is a test");
                //Change the graphic
                label.setGraphic(temp);

                temp.requestFocus();
                // I want the caret to be at the end. In reality it will
                // be but at screen it will be at the beginning the first time.
                temp.end();
            }
        });
        label.setFont(new Font("Arial", 20));

        final VBox vbox = new VBox();
        vbox.setSpacing(5);
        vbox.setPadding(new Insets(10, 0, 0, 10));
        vbox.getChildren().addAll(label);

        ((Group) scene.getRoot()).getChildren().addAll(vbox);

        stage.setScene(scene);
        stage.show();
    }
}