src/vs/workbench/contrib/files/browser/views/explorerViewer.ts/CompressedNavigationController/updateCollapsed
class CompressedNavigationController:	updateCollapsed(collapsed: boolean): void {
		this.collapsed = collapsed;
		for (let i = 0; i < this.labels.length; i++) {
			this.labels[i].setAttribute('aria-expanded', collapsed ? 'false' : 'true');
		}
	}