java.lang.RuntimeException: dndGesture.dragboard is null in dragDrop

FULL PRODUCT VERSION :
java version "1.8.0_60"
Java(TM) SE Runtime Environment (build 1.8.0_60-b27)
Java HotSpot(TM) 64-Bit Server VM (build 25.60-b23, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Mac OS X' Version '10.11.6' Arch 'x86_64'

A DESCRIPTION OF THE PROBLEM :
Using the demo javafx drag and drop example from here: http://docs.oracle.com/javafx/2/drag_drop/HelloDragAndDrop.java.html (source included below)

If you drag a file onto the window and before letting go of the left button, press the right mouse button you get a java crash.

Only happens on MacOSX, have tried the same on Windows 7 & 10 and Linux Mint and they are OK.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Run demo app
2. Drag a file onto the window
3. Before releasing left mouse button, press the right mouse button.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Shouldn't crash
ACTUAL -
Crashes

ERROR MESSAGES/STACK TRACES THAT OCCUR :
java.lang.RuntimeException: dndGesture.dragboard is null in dragDrop
    at javafx.scene.Scene$DropTargetListener.drop(Scene.java:2863) ~[jfxrt.jar:?]
    at com.sun.javafx.tk.quantum.GlassSceneDnDEventHandler.lambda$handleDragDrop$309(GlassSceneDnDEventHandler.java:95) ~[jfxrt.jar:?]
    at java.security.AccessController.doPrivileged(Native Method) ~[?:1.8.0_101]
    at com.sun.javafx.tk.quantum.GlassSceneDnDEventHandler.handleDragDrop(GlassSceneDnDEventHandler.java:92) ~[jfxrt.jar:?]
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleDragDrop$363(GlassViewEventHandler.java:700) ~[jfxrt.jar:?]
    at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389) ~[jfxrt.jar:?]
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleDragDrop(GlassViewEventHandler.java:699) ~[jfxrt.jar:?]
    at com.sun.glass.ui.View.handleDragDrop(View.java:712) ~[jfxrt.jar:?]
    at com.sun.glass.ui.View.notifyDragDrop(View.java:1037) ~[jfxrt.jar:?]

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package hellodraganddrop;

import javafx.application.Application;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.input.*;
import javafx.scene.paint.Color;
import javafx.scene.text.Text;
import javafx.stage.Stage;

/**
 * Demonstrates a drag-and-drop feature.
 */
public class HelloDragAndDrop extends Application {

    @Override public void start(Stage stage) {
        stage.setTitle("Hello Drag And Drop");

        Group root = new Group();
        Scene scene = new Scene(root, 400, 200);
        scene.setFill(Color.LIGHTGREEN);

        final Text source = new Text(50, 100, "DRAG ME");
        source.setScaleX(2.0);
        source.setScaleY(2.0);

        final Text target = new Text(250, 100, "DROP HERE");
        target.setScaleX(2.0);
        target.setScaleY(2.0);

        source.setOnDragDetected(new EventHandler <MouseEvent>() {
            public void handle(MouseEvent event) {
                /* drag was detected, start drag-and-drop gesture*/
                System.out.println("onDragDetected");
                
                /* allow any transfer mode */
                Dragboard db = source.startDragAndDrop(TransferMode.ANY);
                
                /* put a string on dragboard */
                ClipboardContent content = new ClipboardContent();
                content.putString(source.getText());
                db.setContent(content);
                
                event.consume();
            }
        });

        target.setOnDragOver(new EventHandler <DragEvent>() {
            public void handle(DragEvent event) {
                /* data is dragged over the target */
                System.out.println("onDragOver");
                
                /* accept it only if it is not dragged from the same node
                 * and if it has a string data */
                if (event.getGestureSource() != target &&
                        event.getDragboard().hasString()) {
                    /* allow for both copying and moving, whatever user chooses */
                    event.acceptTransferModes(TransferMode.COPY_OR_MOVE);
                }
                
                event.consume();
            }
        });

        target.setOnDragEntered(new EventHandler <DragEvent>() {
            public void handle(DragEvent event) {
                /* the drag-and-drop gesture entered the target */
                System.out.println("onDragEntered");
                /* show to the user that it is an actual gesture target */
                if (event.getGestureSource() != target &&
                        event.getDragboard().hasString()) {
                    target.setFill(Color.GREEN);
                }
                
                event.consume();
            }
        });

        target.setOnDragExited(new EventHandler <DragEvent>() {
            public void handle(DragEvent event) {
                /* mouse moved away, remove the graphical cues */
                target.setFill(Color.BLACK);
                
                event.consume();
            }
        });
        
        target.setOnDragDropped(new EventHandler <DragEvent>() {
            public void handle(DragEvent event) {
                /* data dropped */
                System.out.println("onDragDropped");
                /* if there is a string data on dragboard, read it and use it */
                Dragboard db = event.getDragboard();
                boolean success = false;
                if (db.hasString()) {
                    target.setText(db.getString());
                    success = true;
                }
                /* let the source know whether the string was successfully
                 * transferred and used */
                event.setDropCompleted(success);
                
                event.consume();
            }
        });

        source.setOnDragDone(new EventHandler <DragEvent>() {
            public void handle(DragEvent event) {
                /* the drag-and-drop gesture ended */
                System.out.println("onDragDone");
                /* if the data was successfully moved, clear it */
                if (event.getTransferMode() == TransferMode.MOVE) {
                    source.setText("");
                }
                
                event.consume();
            }
        });

        root.getChildren().add(source);
        root.getChildren().add(target);
        stage.setScene(scene);
        stage.show();
    }

    public static void main(String[] args) {
        Application.launch(args);
    }
}
---------- END SOURCE ----------