Prevent double opening of JavaFX 8 ContextMenu

Question

I am using a JavaFX ContextMenu with a GridPane, on the GridPane I also am placing Rectangles that have ContextMenus of their own. Both context menus fire on a click of the right mouse button.

The event handler on the GridPane looks like this:

this.addEventHandler(MouseEvent.MOUSE_CLICKED, event -> { 
    if (event.getButton().equals(MouseButton.SECONDARY)) {
          ContextMenu cm = new ContextMenu();
          MenuItem newElement = new MenuItem("Add Element");
          addElement.setOnAction(menuEvent -> { /* Logic for handling context menu action */ });
          cm.getItems.add(newElement);
          cm.show(this,event.getScreenX(),event.getScreenY());
    } 
});

The event handler on the Rectangle on the grid looks like this:

this.addEventHandler(MouseEvent.MOUSE_CLICKED, event -> {
     // Right click
     if (event.getButton().equals(MouseButton.SECONDARY)) {
        this.requestFocus();
        ContextMenu cm = new ContextMenu();

        MenuItem toRemove = new MenuItem("Delete Element");
        toRemove .setOnAction(menuEvent -> {
             /* Logic for removing element */
        });

        cm.getItems().add(toRemove );
        cm.show(this, event.getScreenX(), event.getScreenY());
     }
  });

How do I ensure that only the context menu for the element that is on the GridPane is shown if the right click is on that element?

Answer 1

Since events are propagated upwards according to:

https://docs.oracle.com/javase/8/javafx/events-tutorial/processing.htm

It is necessary to add:

event.consume();

at the end of the handler for the element on the grid so that the right click event does not continue to propagate to the event handler for the GridPane.