Mac-catalyst remove tabbing

Question

I developed my App originally with Xcode 12.4, meaning mac-catalyst 13.6 and/or iOS 13.6.

However, after upgrading to Xcode 16.4, meaining mac-catalyst 15.x, now the Root-window suddenly shows tabbing:

MyApp

I tried to fix remove tabbing like:

let window = NSApplication.shared.mainWindow;
assert(window != nil);
window.tabbingMode = .disallowed;
window.toggleTabBar(nil);

Additionally, since maybe mainWindow was wrong, I tried same but for all Windows:

NotificationCenter.default.addObserver(
 forName: NSWindow.didBecomeKeyNotification,
 object: nil,
 queue: .main
) { [weak self] note in
 guard let newWindow = note.object as? NSWindow
 else { return }
 for var window in NSApplication.shared.windows {
 // ...
 }
}

• HangarRash: This is kind of a duplicate of stackoverflow.com/questions/61175725/… but you want the opposite. See my answer to that question. You want to set the property to No instead of Yes.

Answer 1

Seems UIApplicationSupportsTabbedSceneCollection is true by default in newer Xcode versions (if it's unset), and setting UIApplicationSupportsTabbedSceneCollection to false did fixed the issue.

(as suggested by hangarrash.)

Example:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
 <dict>
 <key>UISceneConfigurations</key>
 <dict/>
 <key>UIApplicationSupportsMultipleScenes</key>
 <true/>
 <key>UIApplicationSupportsTabbedSceneCollection</key>
 <false/>
 </dict>
</dict>
</plist>