diff --git a/CLAUDE.md b/CLAUDE.md
index 75e277d..3ff7b25 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -64,7 +64,7 @@ Release pipeline is documented in `DeveloperRelease.md`. One published GitHub Re
 - `Assets.xcassets/AppIcon`
 
 `KVMConsoleiPad/` — iPadOS app target.
-- `App/KVMConsoleiPadApp.swift` — single `WindowGroup` with a `NavigationStack`; the Connection list pushes the Viewer (one connection at a time, no multi-scene)
+- `App/KVMConsoleiPadApp.swift` — two scenes mirroring macOS: a `WindowGroup` Connections list plus a value-parameterized `WindowGroup("Viewer", for: Device.ID.self)`; connecting opens a separate viewer window so devices run side-by-side under Stage Manager (`UIApplicationSupportsMultipleScenes`)
 - `UI/` — `ViewerView`, `ViewerHostView`, `ModifierKeyBar` (Ctrl/Alt/Cmd/Shift/Win on-screen bar, tap = momentary, long-press = lock)
 - `Input/` — `KeyboardCaptureView` (`UIPress`/`UIKey`), `PointerCaptureView` (`UIHover`/`UIPan`/`UITap`)
 - `Video/VideoRenderView.swift` — `UIViewRepresentable` wrapper over `SampleBufferDisplay`
@@ -81,4 +81,4 @@ Release pipeline is documented in `DeveloperRelease.md`. One published GitHub Re
 - NanoKVM API responses follow NanoKVM's `{code, msg, data}` envelope — see `NanoKVMClient`; GLKVM uses PiKVM-shaped REST and WebSocket messages.
 - Passwords are stored per-device in the Keychain via `KeychainPasswordStore`, never in the saved-devices JSON.
 - macOS fullscreen exit is triple-Escape (`FullscreenKeyCapture`). iPad has no fullscreen capture mode.
-- iPad supports a single active KVM connection at a time (single-scene NavigationStack); macOS allows multiple viewer windows side-by-side.
+- Both platforms support multiple simultaneous viewer windows. On iPad an inactive (backgrounded) viewer pauses its stream via `ScenePhasePausePolicy` (scene-phase-driven `disconnect()`/`reconnect()`) and auto-resumes only the sessions it paused; `.inactive` is ignored so true side-by-side windows keep streaming.
diff --git a/KVMConsoleiPad/App/KVMConsoleiPadApp.swift b/KVMConsoleiPad/App/KVMConsoleiPadApp.swift
index a6de468..a7021d5 100644
--- a/KVMConsoleiPad/App/KVMConsoleiPadApp.swift
+++ b/KVMConsoleiPad/App/KVMConsoleiPadApp.swift
@@ -4,20 +4,25 @@ import SwiftUI
 @main
 struct KVMConsoleiPadApp: App {
     @StateObject private var devicesStore = SavedDevicesStore()
-    @State private var connectedDeviceID: Device.ID?
 
     var body: some Scene {
-        WindowGroup("KVM Console") {
+        // Connections list. Connecting to a device opens a separate Viewer window
+        // (ConnectionManagerView falls back to openWindow(value:) when given no
+        // onConnect callback), so two devices can run side-by-side under Stage Manager.
+        WindowGroup("KVM Console", id: "connections") {
             NavigationStack {
-                ConnectionManagerView { device in
-                    connectedDeviceID = device.id
-                }
-                .environmentObject(devicesStore)
-                .navigationDestination(item: $connectedDeviceID) { deviceID in
-                    ViewerHostView(deviceID: deviceID)
-                        .environmentObject(devicesStore)
-                }
+                ConnectionManagerView()
             }
+            .environmentObject(devicesStore)
+        }
+
+        // One Viewer window per Device.ID. Wrapped in its own NavigationStack so the
+        // viewer's toolbar renders inside the new window rather than the Connections nav.
+        WindowGroup("Viewer", id: "viewer", for: Device.ID.self) { $deviceID in
+            NavigationStack {
+                ViewerHostView(deviceID: deviceID)
+            }
+            .environmentObject(devicesStore)
         }
     }
 }
diff --git a/KVMConsoleiPad/Input/PhysicalKeyboardObserver.swift b/KVMConsoleiPad/Input/PhysicalKeyboardObserver.swift
index 37bf9af..4882f9d 100644
--- a/KVMConsoleiPad/Input/PhysicalKeyboardObserver.swift
+++ b/KVMConsoleiPad/Input/PhysicalKeyboardObserver.swift
@@ -10,7 +10,9 @@ import GameController
 final class PhysicalKeyboardObserver: ObservableObject {
     @Published private(set) var isConnected: Bool
 
-    private var observers: [NSObjectProtocol] = []
+    // `nonisolated(unsafe)`: this @MainActor class's deinit is nonisolated and must
+    // remove its observers; deinit has exclusive access, so the unchecked access is safe.
+    private nonisolated(unsafe) var observers: [NSObjectProtocol] = []
 
     init() {
         isConnected = GCKeyboard.coalesced != nil
diff --git a/KVMConsoleiPad/Resources/Info.plist b/KVMConsoleiPad/Resources/Info.plist
index 640b86a..097aa78 100644
--- a/KVMConsoleiPad/Resources/Info.plist
+++ b/KVMConsoleiPad/Resources/Info.plist
@@ -33,6 +33,11 @@
 	</dict>
 	<key>NSLocalNetworkUsageDescription</key>
 	<string>KVM Console connects to your KVM device over the local network.</string>
+	<key>UIApplicationSceneManifest</key>
+	<dict>
+		<key>UIApplicationSupportsMultipleScenes</key>
+		<true/>
+	</dict>
 	<key>UILaunchScreen</key>
 	<dict/>
 	<key>UISupportedInterfaceOrientations</key>
diff --git a/KVMConsoleiPad/UI/ScenePhasePausePolicy.swift b/KVMConsoleiPad/UI/ScenePhasePausePolicy.swift
new file mode 100644
index 0000000..491ae2d
--- /dev/null
+++ b/KVMConsoleiPad/UI/ScenePhasePausePolicy.swift
@@ -0,0 +1,29 @@
+import SwiftUI
+
+/// What the viewer should do with its stream in response to a scene-phase change.
+enum BackgroundPauseAction: Equatable {
+    case none
+    case pause
+    case resume
+}
+
+/// Pure decision for pausing/resuming a viewer's KVM stream as its window moves
+/// between scene phases. Kept separate from the view so the rule is unit-testable.
+///
+/// `.inactive` is deliberately ignored: it fires transiently (App Switcher, Control
+/// Center, multitasking gestures) and for genuinely side-by-side windows both scenes
+/// stay `.active`, so we only pause on a real `.background`.
+enum ScenePhasePausePolicy {
+    static func action(phase: ScenePhase, sessionIsLive: Bool, isPaused: Bool) -> BackgroundPauseAction {
+        switch phase {
+        case .background:
+            return sessionIsLive ? .pause : .none
+        case .active:
+            return isPaused ? .resume : .none
+        case .inactive:
+            return .none
+        @unknown default:
+            return .none
+        }
+    }
+}
diff --git a/KVMConsoleiPad/UI/ViewerView.swift b/KVMConsoleiPad/UI/ViewerView.swift
index dc8420d..452810f 100644
--- a/KVMConsoleiPad/UI/ViewerView.swift
+++ b/KVMConsoleiPad/UI/ViewerView.swift
@@ -34,10 +34,14 @@ struct ViewerHostView: View {
 struct ViewerView: View {
     @StateObject private var model: ViewerViewModel
     @StateObject private var keyboardObserver = PhysicalKeyboardObserver()
+    @Environment(\.scenePhase) private var scenePhase
     @State private var modifierState = ModifierKeyState()
     @State private var showModifierBar = true
     @State private var keyboardFocusToken = 0
     @State private var pendingVirtualKey: VirtualKeyTap?
+    // True only while a stream was paused because THIS window went to the background,
+    // so we auto-resume on return without reviving a manually-disconnected session.
+    @State private var pausedForBackground = false
 
     init(device: Device, onConnected: ((Device.ID) -> Void)? = nil) {
         _model = StateObject(wrappedValue: ViewerViewModel(device: device, onConnected: onConnected))
@@ -66,11 +70,32 @@ struct ViewerView: View {
         .background(Color.black)
         .navigationBarTitleDisplayMode(.inline)
         .toolbar { toolbarContent }
+        .onChange(of: scenePhase) { _, newPhase in
+            handleScenePhase(newPhase)
+        }
         .onDisappear {
             model.disconnect()
         }
     }
 
+    private func handleScenePhase(_ phase: ScenePhase) {
+        let sessionIsLive = model.isStreaming || model.state == .connecting
+        switch ScenePhasePausePolicy.action(
+            phase: phase,
+            sessionIsLive: sessionIsLive,
+            isPaused: pausedForBackground
+        ) {
+        case .pause:
+            pausedForBackground = true
+            model.disconnect()
+        case .resume:
+            pausedForBackground = false
+            model.reconnect()
+        case .none:
+            break
+        }
+    }
+
     private var videoArea: some View {
         ZStack {
             Color.black
diff --git a/KVMConsoleiPadTests/ScenePhasePausePolicyTests.swift b/KVMConsoleiPadTests/ScenePhasePausePolicyTests.swift
new file mode 100644
index 0000000..858e32b
--- /dev/null
+++ b/KVMConsoleiPadTests/ScenePhasePausePolicyTests.swift
@@ -0,0 +1,44 @@
+@testable import KVMConsoleiPad
+import SwiftUI
+import XCTest
+
+final class ScenePhasePausePolicyTests: XCTestCase {
+    func test_backgroundWithLiveSessionPauses() {
+        XCTAssertEqual(
+            ScenePhasePausePolicy.action(phase: .background, sessionIsLive: true, isPaused: false),
+            .pause
+        )
+    }
+
+    func test_backgroundWithIdleSessionDoesNothing() {
+        XCTAssertEqual(
+            ScenePhasePausePolicy.action(phase: .background, sessionIsLive: false, isPaused: false),
+            .none
+        )
+    }
+
+    func test_activeWhilePausedResumes() {
+        XCTAssertEqual(
+            ScenePhasePausePolicy.action(phase: .active, sessionIsLive: false, isPaused: true),
+            .resume
+        )
+    }
+
+    func test_activeWhenNotPausedDoesNothing() {
+        XCTAssertEqual(
+            ScenePhasePausePolicy.action(phase: .active, sessionIsLive: true, isPaused: false),
+            .none
+        )
+    }
+
+    func test_inactiveIsIgnored() {
+        XCTAssertEqual(
+            ScenePhasePausePolicy.action(phase: .inactive, sessionIsLive: true, isPaused: false),
+            .none
+        )
+        XCTAssertEqual(
+            ScenePhasePausePolicy.action(phase: .inactive, sessionIsLive: false, isPaused: true),
+            .none
+        )
+    }
+}
diff --git a/project.yml b/project.yml
index bdc1f24..0222292 100644
--- a/project.yml
+++ b/project.yml
@@ -96,6 +96,8 @@ targets:
         ITSAppUsesNonExemptEncryption: false
         GCSupportsControllerUserInteraction: true
         LSRequiresIPhoneOS: true
+        UIApplicationSceneManifest:
+          UIApplicationSupportsMultipleScenes: true
         NSAppTransportSecurity:
           NSAllowsArbitraryLoads: true
         NSLocalNetworkUsageDescription: "KVM Console connects to your KVM device over the local network."