src/vs/base/browser/ui/tree/indexTreeModel.ts/IndexTreeModel/_getLastElementAncestor
class IndexTreeModel:	private _getLastElementAncestor(node: ITreeNode<T, TFilterData>): T {
		if (node.children.length === 0) {
			return node.element;
		}

		return this._getLastElementAncestor(node.children[node.children.length - 1]);
	}