[WebView] Outstanding resource locks detected

I' m getting this error when opening a web page using WebView:

Outstanding resource locks detected:
D3D Vram Pool: 17.885.568 used (6,7%), 17.885.568 managed (6,7%), 268.435.456 total
14 total resources being managed
average resource age is 0,8 frames
0 resources at maximum supported age (0,0%)
7 resources marked permanent (50,0%)
2 resources have had mismatched locks (14,3%)
2 resources locked (14,3%)
8 resources contain interesting data (57,1%)
0 resources disappeared (0,0%)

Here is the code that reproduces the problem:

package sample;

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.StackPane;
import javafx.scene.web.WebView;
import javafx.stage.Stage;

public class Main extends Application {

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

        StackPane stackPane = new StackPane();
        WebView webView = new WebView();
        stackPane.getChildren().addAll(webView);

        webView.getEngine().load("http://dygraphs.com/");

        primaryStage.setTitle("Hello World");
        primaryStage.setScene(new Scene(stackPane, 800, 480));
        primaryStage.show();
    }

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

The page loaded is "http://dygraphs.com/" and it's supposed to show some lines in the chart but they are not being showed and this error is thrown.