1) Run the sample demo application below
2) Click on the "open popup" button
3) Navigate in the list using the MacBook touchpad (two fingers up/down)
4) NullPointerException occurred

[Logs]
Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
at com.sun.glass.ui.TouchInputSupport.notifyBeginTouchEvent(TouchInputSupport.java:82)
at com.sun.glass.ui.mac.MacTouchInputSupport.notifyEndTouchEvent(MacTouchInputSupport.java:85)
at com.sun.glass.ui.mac.MacGestureSupport.notifyEndTouchEvent(MacGestureSupport.java:81)
(repeated thousand of time)

[Demo.java]
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.ListView;
import javafx.scene.control.PopupControl;
import javafx.scene.control.Skin;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class Demo extends Application {
    class MyPopupControlSkin implements Skin<PopupControl> {
        private final PopupControl popupControl;
        private final Node node;
        public MyPopupControlSkin(final PopupControl control) {
            this.popupControl = control;
            ObservableList<Number> data = FXCollections.observableArrayList();
            for( int i = 0; i < 400; i++ ) {
                data.add(i);
            }
            this.node = new VBox(new Label("Popup control"), new ListView(data));
        }
        @Override public PopupControl getSkinnable() {
            return popupControl;
        }
        @Override public Node getNode() {
            return node;
        }
        @Override public void dispose() {}
    }
     
    @Override public void start(Stage primaryStage) {
        Button btn = new Button("Open popup");
        btn.setOnAction((ActionEvent e) -> {
            PopupControl popup = new PopupControl();
            popup.setSkin(new MyPopupControlSkin(popup));
            popup.show(btn, primaryStage.getX() + 160, primaryStage.getY() + 30);
        });
        primaryStage.setScene(new Scene(btn, 150, 50));
        primaryStage.show();
    }

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