Border and background is modified with the ProgressIndicator

Run this sample :

import javafx.application.Application;
import static javafx.application.Application.launch;
import javafx.scene.Scene;
import javafx.scene.control.ProgressIndicator;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

public class TestProgress extends Application {

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

    @Override
    public void start(Stage primaryStage) throws Exception {
        ProgressIndicator pi = new ProgressIndicator(-1);
        pi.setMaxHeight(50);
        BorderPane pane = new BorderPane(pi);

        Scene scene = new Scene(pane);
        primaryStage.setScene(scene);
        primaryStage.setMinHeight(300);
        primaryStage.setMinWidth(100);
        primaryStage.show();
    }
}


In 8u20, the progress indicator is blending perfectly with the overall background. In latest 8u40 (b05), the progress indicator is surrounded by a white framework.

Is this a normal behavior? If yes, can you please explain which are the modification so that people can retrieve the 8u20 behavior.