SwiftUI / iOS 13 - NotificationCenter with Multiple Scenes - ipad

Question

With the introduction of iOS 13, a single app can have multiple scenes. In particular, on the iPad, you can run 2 scenes of an app side by side.
This creates a problem in my app with NotificationCenter. A NotificationCenter event is shared by across all scenes. While this could be useful syncing data across scenes, some events that are intended to be responded within the original scene are handled by all 2 scenes.
For example, in this custom UIHostingController class, I have a function to handle UIKeyCommands and post a Notification to the NotificationCenter.
class HostingController: UIHostingController<ContentView> {
override var keyCommands: [UIKeyCommand]? {
var result: [UIKeyCommand] = [
UIKeyCommand(
title: "New File",
action: #selector(handleNotification),
input: "N",
modifierFlags: [.command],
discoverabilityTitle: "New File"
)
]
}
#objc func handleNotification(sender: UIKeyCommand){
NotificationCenter.default.post(name: Notification.Name.handleKeyboardShortcut, object: sender.title)
}
}
This event is then handled by an UI element in ContentView.
var body: some View {
ZStack(){
...
}.onReceive(NotificationCenter.default.publisher(for: Notification.Name.handleKeyboardShortcut)) { notification in
if let shortcutKey = notification.object as? String {
switch shortcutKey {
case "New File":
self.openNewFile()
case "Show Panel":
self.openConsolePanel()
...
default:
break
}
}
}
Then the problem arises, when pressing Command + N while running 2 scenes of the app side-by-side, both scenes' openNewFile function is fired. Both instances pop up an file selection sheet. This is obviously an undesirable behavior.
I have a few ideas regarding the issue.
Check if the scene is last interacted, and only call the function openNewFile if so.
Handle UIKeyCommands outside HostingController, since it's shared by all scenes. In particular, I want to use addKeyCommand(_:) equivalent methods inside ContentView so that the UIKeyCommands can be dynamically changed.
I don't quite know how implement these though. What could be the best way to handle the problem?