I have a fully working FileProvider on iOS11 and I can serve up files and save them back with one exception. When I open my FileProvider in the Files.app I cannot paste or drag items into it. I get a little "not allowed" icon. If I try to Paste, the only menu option is "Info".Also, when I save a document from an application (e.g. Word), the Move button does not appear.I have implemented allowsAll on all my FileProviderItem objects:var capabilities: NSFileProviderItemCapabilities { return .allowsAll }and my FileProviderExtension implements importDocument, but it is NEVER called: override func importDocument(at fileURL: URL, toParentItemIdentifier parentItemIdentifier: NSFileProviderItemIdentifier, completionHandler: @escaping (NSFileProviderItem?, Error?) -> Void) { print("###\(#function): URL = \(fileURL), parentItemIdentifier = \(parentItemIdentifier)") completionHandler(nil, nil) }I also notice that the create folder button is disabled.What are the minimal requirements to allow new files?