} else if (host instanceof IRootPart) {
			// check if click on background (either one of the root visuals, or
			// an unregistered visual)
			Map<Node, IVisualPart<Node, ? extends Node>> visualPartMap = getHost()
					.getRoot().getViewer().getVisualPartMap();
			IVisualPart<Node, ? extends Node> targetPart = visualPartMap
					.get(e.getTarget());
			if (targetPart == null || targetPart == host) {
				// unset focus
				focusModel.setFocus(null);
				// remove all selected
				selectionModel.clearSelection();
			}
		}

public void hover(MouseEvent e) {
	// do nothing in case there is an explicit event target
	if (isRegistered(e.getTarget()) && !isRegisteredForHost(e.getTarget())) {
		return;
	}
	// ...
}

	private void unregisterVisuals() {
		Map<Node, IVisualPart<Node, ? extends Node>> visualPartMap = getRoot().getViewer().getVisualPartMap();
		Set<Node> keySet = new HashSet<>(visualPartMap.keySet());
		for (Node visual : keySet) {
			if (visualPartMap.get(visual) == this) {
				visualPartMap.remove(visual);
			}
		}
	}
	
	private void registerVisuals(Node visual) {
		Map<Node, IVisualPart<Node, ? extends Node>> visualPartMap = getRoot().getViewer().getVisualPartMap();
		visualPartMap.put(visual, this);
		if (visual instanceof Parent) {
			for (Node child : ((Parent) visual).getChildrenUnmodifiable()) {
				registerVisuals(child);
			}
		}
	}
	
	private void updateRegistration() {
		unregisterVisuals();
		registerVisuals(getVisual());
	}

private final ListChangeListener<Node> curveNodeChildrenObserver = new ListChangeListener<Node>() {

		@Override
		public void onChanged(ListChangeListener.Change<? extends Node> c) {
			Map<Node, IVisualPart<Node, ? extends Node>> visualPartMap = getHost()
					.getRoot().getViewer().getVisualPartMap();
			// ensure clickable area is properly registered/unregistered at/from
			// visual part map.
			while (c.next()) {
				for (Node n : c.getRemoved()) {
					visualPartMap.remove(n);
				}
				for (Node n : c.getAddedSubList()) {
					visualPartMap.put(n, getHost());
				}
			}
		}
	};

	protected final ListChangeListener<Node> nodeChildrenListener = (change) -> updateOnChange(change);

	protected void updateOnChange(Change<? extends Node> change) {
		IViewer<Node> viewer = getRoot().getViewer();
		while (change.next()) {
			for (Node removedNode : change.getRemoved()) {
				unregisterVisuals(viewer, removedNode);
			}

			for (Node addedNode : change.getAddedSubList()) {
				registerVisuals(viewer, addedNode);
			}
		}
	}

	@Override
	protected void registerAtVisualPartMap(IViewer<Node> viewer, N visual) {
		// Override the parent behavior to ensure that listeners are properly installed when required
		registerVisuals(viewer, visual);
	}

	@Override
	protected void unregisterFromVisualPartMap(IViewer<Node> viewer, N visual) {
		// Override the parent behavior to ensure that listeners are properly uninstalled
		unregisterVisuals(viewer, visual);
	}

	protected void unregisterVisuals(IViewer<Node> viewer, Node visual) {
		Map<Node, IVisualPart<Node, ? extends Node>> visualPartMap = viewer.getVisualPartMap();

		// Do not unregister child content parts; only child figures for this content part
		if (visualPartMap.get(visual) == this) {
			visualPartMap.remove(visual);

			if (visual instanceof Parent) {
				Parent parentVisual = (Parent) visual;
				for (Node childNode : parentVisual.getChildrenUnmodifiable()) {
					unregisterVisuals(viewer, childNode);
				}
				parentVisual.getChildrenUnmodifiable().removeListener(nodeChildrenListener);
			}
		}
	}

	protected void registerVisuals(IViewer<Node> viewer, Node visual) {
		Map<Node, IVisualPart<Node, ? extends Node>> visualPartMap = viewer.getVisualPartMap();

		IVisualPart<Node, ? extends Node> currentPart = visualPartMap.get(visual);
		if (currentPart == null) { // Not yet registered
			visualPartMap.put(visual, this);
		}

		if (visual instanceof Parent && (currentPart == null || currentPart == this)) { // Do not register nested visuals if they are associated with a child part
			Parent parentVisual = (Parent) visual;
			parentVisual.getChildrenUnmodifiable().addListener(nodeChildrenListener);
			for (Node child : parentVisual.getChildrenUnmodifiable()) {
				registerVisuals(viewer, child);
			}
		}
	}