Further work has indicated that setSelectionIndex is not to blame - see question 'No functions in class called in app developed in Monterey running on Catalina'

Turns out the problem had nothing to do with MacOS version - the Catalina instance was trying to write a file to a folder with no write access and the success of the write was not being tested. The resulting error came much later. The problem was resolved by installing Xcode 12.3 on the Catalina instance and running the app from inside it, stopping to inspect values at various stages. Ignore this question...

Aug 26 2022 - Currently in 21st day of waiting for a new iOS app review. Received a message saying only "We need more time'. Curiously a MacOS app was reviewed within 24 hrs - does Apple treat iOS apps and MacOS apps differently? And are upgrades treated differently from new apps? Is Apple under attack for being sole gatekeeper to the iOS platform?

After the initial immediate rejection and the resolution message 'We need additional time to evaluate your submission and Apple Developer Program account. Your submission status will appear as "Rejected" in App Store Connect while we investigate. However, we do not require a revised binary or additional information from you at this time. ' , I noticed the Submit for Review button was enabled and clicked submit on 21 August.

The status then changed to In Review and on Sep 5 the iOS app was reviewed (and rejected). Whether this took 10 or 31 days I don't know. New version submitted on 7 Sep with no immediate rejection so we'll see how this one goes

The latest submission was reviewed in less than 24 hours - perhaps I was just unlucky

If I set the UIPickerView height to 162 I get the bizarre message [UIPickerView setFrame:]: invalid size {204,162} pinned to {204,162} but the height does not change. Looks like an Apple bug.

id code was missing a digit - works OK

Found a fudge solution which was to add [level 3 form setIsVisible: false] to the routine executed by NSWindowWillClose notification for level 3 form

The action function is called if the click occurs in the place where the UIBarButton was before the origin was shifted