src/vs/base/browser/ui/tree/indexTree.ts/IndexTree/createModel
class IndexTree:	protected createModel(user: string, view: IList<ITreeNode<T, TFilterData>>, options: IIndexTreeOptions<T, TFilterData>): ITreeModel<T, TFilterData, number[]> {
		return new IndexTreeModel(user, view, this.rootElement, options);
	}