this.setLayoutManager(new XYLayout() {
	
	// Disallow to drag child nodes out of the figure
	@Override
	public Object getConstraint(IFigure figure) {
		Rectangle result = (Rectangle) constraints.get(figure);
		if (result == null) {
			result = new Rectangle(0, 0, -1, -1);
		} else {
			if(result.x < 0) {
				result.x = 0;
			}
			if(result.y < 0) {
				result.y = 0;
			}						
		}
		return result;
	}
});