src/vs/workbench/contrib/bulkEdit/browser/preview/bulkEditPane.ts/BulkEditPane/_setTreeInput
class BulkEditPane:	private async _setTreeInput(input: BulkFileOperations) {

		const viewState = this._treeViewStates.get(this._treeDataSource.groupByFile);
		await this._tree.setInput(input, viewState);
		this._tree.domFocus();

		if (viewState) {
			return;
		}

		// async expandAll (max=10) is the default when no view state is given
		const expand = [...this._tree.getNode(input).children].slice(0, 10);
		while (expand.length > 0) {
			const { element } = expand.shift()!;
			if (element instanceof FileElement) {
				await this._tree.expand(element, true);
			}
			if (element instanceof CategoryElement) {
				await this._tree.expand(element, true);
				expand.push(...this._tree.getNode(element).children);
			}
		}
	}