def on_object_removed(event)
      object = event.target
      object.traverse do |child|
        child.remove_event_listener(:remove, method(:on_object_removed))
        remove_child(child)
      end
    end
def on_object_removed(event)
      object = event.target
      object.traverse do |child|
        child.remove_event_listener(:remove, method(:on_object_removed))
        remove_child(child)
      end
    end
Events