src/vs/workbench/contrib/search/browser/searchView.ts/SearchView/hasSomeCollapsible
class SearchView:	private hasSomeCollapsible(): boolean {
		const viewer = this.getControl();
		const navigator = viewer.navigate();
		let node = navigator.first();
		do {
			if (!viewer.isCollapsed(node)) {
				return true;
			}
		} while (node = navigator.next());

		return false;
	}