No. that UI isn't webview. so could not control by WKUIDelegate. I check log message that with console app, it seems to 'SOAuthorization' in private framework. -[SOUIAuthorizationViewController viewWillDisappear] on <private> -[SOUIAuthorizationViewController viewDidDisappear] on <private> -[SOAuthorization viewControllerDidCancel:] viewController = <SOUIAuthorizationViewController: 0x7fcb280110f0>, authorizationViewController = (null) on <private> This private framework seem to not provide public API.. There is probably no way to handle the cancel action..