With membership in the Apple developer program, Xcode can create any necessary signing certificates for you. You mentioned the Mac store, but you used the Notarization tag, and you need to understand that those are two separate alternatives. So your first decision is whether you will distribute your software on the Mac App Store or on some other web site. Start here: https://developer.apple.com/macos/distribution/

@eskimo Thanks! What I ended up doing is using a delayed perform (which, I gather, uses another timer behind the scenes) to run the dialog. Then my timer fires both inside and outside the dialog.

The suggestions by @galad87 are good. I would add that you could set a symbolic breakpoint on -[NSObject doesNotRecognizeSelector:]. I haven't actually tried that, but in theory it should work.

You can specify the entitlement com.apple.security.files.downloads.read-write for access to Downloads, but there is no similar entitlement for Desktop.

OK, it looks like the problem was that this private tool was not code signed at all. I had no idea that would affect Open Recent.

It looks like you're trying to archive a plug-in, not an app. That's why you can't make an app archive. If you need to notarize it, you won't be able to do it using Xcode, you will need to use a more manual approach. See: https://developer.apple.com/documentation/security/notarizing_macos_software_before_distribution/customizing_the_notarization_workflow?language=objc

I'm still having this problem in an outline table with no action or double action and with an implementation of outlineView:pasteboardWriterForItem:.

There is a ScreenCaptureKit framework, but I wouldn’t exactly say it’s the same functionality, it looks way more complicated.

When your device is connected, does in show up in the Game Controllers panel of the System Settings app?

Those buttons, together with the gray box below, are called a "tab view", implemented by the class NSTabView. You can also do something similar without the box as a "segmented control", class NSSegmentedControl. You can read about the kinds of controls (and what Apple calls them) in the Human Interface Guidelines.

I don't have a solution, but I wanted to mention another complication: Another place you can see certificates is in the Keychain Access utility. I deleted an expired certificate there, but it still shows up in Xcode, with a status of "Missing private key". And the "Delete Certificate" contextual menu item is still dimmed.

Have you considered that there may be space between columns? See the intercellSpacing property.

You can call the units "points", but they do not necessarily have anything to do with printer's points. To see how they correspond to hardware pixels, you look at the "backing" coordinate system, with methods such as convertPointToBacking:.

When you see the archive in the Organizer window, is it described as an app archive or a generic archive? If it’s the latter, see this article: https://developer.apple.com/documentation/technotes/tn3110-resolving-generic-xcode-archive-issue

Why aren't you using Xcode to notarize your app? That is, in the Organizer window, select the archive, click Distribute App, and when it asks for the method of distribution, select Developer ID. There are some situations where one must use notarytool manually, but it doesn't sound like you're in one of those situations.