A DESCRIPTION OF THE PROBLEM :
With OJFX 12.0.2 when I close the stage, both the stage and the JVM process terminate.
With OJFX 13.0.1 when I close the stage, the stage closes but the JVM process keeps running.
When I don't create the WebView and close the stage, both the stage and JVM process terminate.

REGRESSION : Last worked in version 13.0.1

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run JavaFX application that creates WebView.
Close the primary stage before the WebView is garbage collected.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
JVM process terminates.
ACTUAL -
JVM process keeps running.

---------- BEGIN SOURCE ----------
public class App extends Application {

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

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

        WebView wv = new WebView();
        BorderPane root = new BorderPane();
        root.setCenter(wv);
        Scene scene = new Scene(root, 600, 600);
        stage.setScene(scene);
        stage.show();
    }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Use OpenJFX 12.0.2

FREQUENCY : often