I'm trying to invoke UIBarButtonItem(title:image:primaryAction:menu:) -- which worked just fine with iOS and iPadOS. However, when invoking Mac Catalyst, the compiler is complaining about this statement:
UIBarButtonItem(title: "Files", image: nil, primaryAction: nil, menu: leftItems)
saying that it "Cannot convert value of type 'UIMenu' to expected argument type 'Selector?'.
There's another form of UIBarButtonItem's initializer that does want a selector -- and I'm using that elsewhere -- but the documentation states that this initializer is available for Mac Catalyst.
What's going on?
Thanks for any help.

