Sharing file creates new UIScene each time, how to prevent this

I have an App which supports multiple windows on the iPad. The App can receive URLs from other Apps (via application.openURL()) and also files via "share sheet" (via UIActivityViewController). When receiving a URL from another App the delegate method

scene(_ scene: UIScene, openURLContexts URLContexts: Set<UIOpenURLContext>)

will be called on an existing UIScene, however when a file is received through the share sheet from another App, a new UIScene is created and therefore also a new window (eg the delegates

application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions)

and

scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions)

are called).

In both cases I do get the URL and file just fine, however I do not want to get new UIScenes and windows created when receiving a file via share sheet.

How can I prevent to get a new UIScene or window? The received files should be used in the existing windows and should not create new ones.

Sharing file creates new UIScene each time, how to prevent this
 
 
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