UIDocumentBrowserViewController Bug in Xcode 9 Beta 2?

Hi,

I am having problems with UIDocumentBrowserViewController Bug in Xcode 9
Beta 2, was working with beta 1.

The symptom is that you can't create a new document, on most pages the +
icon is missing or greyed out. On the browse page it is present and not
greyed out, but doesn't work.

EG If you start a new Documents project and modify the function below to
include the print statement given:

    func documentBrowser(_ controller: UIDocumentBrowserViewController,
didRequestDocumentCreationWithHandler importHandler: @escaping (URL?,
UIDocumentBrowserViewController.ImportMode) -> Void) {

        print("creating document")

        ...

Then the print statement isn't printed when + on browse page is tapped.

Testing on iPad Pro 12" (original) with latest iOS 11 beta.

Is this a bug? Am I doing something wrong?

Thanks for any help,

  -- Howard.