@Override
	public List<IOutlineNode> getChildren() {
		if (isLeaf)
			return Collections.emptyList();
		if (children == null) {
			readOnly(new IUnitOfWork.Void<EObject>() {
				@Override
				public void process(EObject eObject) throws Exception {
					getTreeProvider().createChildren(AbstractOutlineNode.this, eObject);
				}
			});
			if (children == null) {
				// tree provider did not create any child
				isLeaf = true;
				return Collections.emptyList();
			}
		}
		return Collections.unmodifiableList(children);
	}