Make the window visible without it becoming the key window of the app.

For the presentation of notifications the window does not have to be key.
It will still receive touch events (gestures, buttons etc) but won't receive keyboard events and motion events.

Sources/UINotificationCenter.swift

@@ -31,7 +31,7 @@ public final class UINotificationCenter {
     // MARK: Private properties
 
     /// The window which will be placed on top of the application window.
-    /// This window is used to present the notifications on and will be hidden when all notifications are presented.
+    /// This window is used to present the notifications on and will be hidden when notifications are dismissed.
     internal let window: UIWindow
 
     /// Handles queueing of all notifications. Contains a queue of `UINotificationRequest` objects.

Sources/UINotificationPresentationContext.swift

@@ -52,7 +52,7 @@ public final class UINotificationPresentationContext {
     private func prepareContainerWindow() {
         containerWindow.windowLevel = windowLevel
         #if !TEST
-            containerWindow.makeKeyAndVisible()
+            containerWindow.isHidden = false
         #endif
     }
 
@@ -94,9 +94,6 @@ public final class UINotificationPresentationContext {
         /// Move the window behind the key application window.
         containerWindow.windowLevel = UIWindow.Level.normal - 1
         containerWindow.rootViewController = nil
-
-        /// Make sure the key window of the app is visible again.
-        guard let applicationWindow = UIApplication.shared.windows.first(where: { $0 != self.containerWindow }) else { return }
-        applicationWindow.makeKeyAndVisible()
+        containerWindow.isHidden = true
     }
 }