src/vs/workbench/contrib/files/browser/views/explorerViewer.ts/ExplorerDataSource/hasChildren
class ExplorerDataSource:	hasChildren(element: ExplorerItem | ExplorerItem[]): boolean {
		// don't render nest parents as containing children when all the children are filtered out
		return Array.isArray(element) || element.hasChildren((stat) => this.fileFilter.filter(stat, TreeVisibility.Visible));
	}