src/vs/workbench/contrib/files/browser/explorerService.ts/ExplorerService/findClosestRoot
class ExplorerService:	findClosestRoot(resource: URI): ExplorerItem | null {
		const parentRoots = this.model.roots.filter(r => this.uriIdentityService.extUri.isEqualOrParent(resource, r.resource))
			.sort((first, second) => second.resource.path.length - first.resource.path.length);
		return parentRoots.length ? parentRoots[0] : null;
	}