FIX: [UUM-145509] Simulator Plugin disabling input devices always.

Assets/Tests/InputSystem/Plugins/DeviceSimulatorTests.cs

@@ -8,6 +8,7 @@
 using UnityEngine.InputSystem;
 using UnityEngine.InputSystem.Editor;
 using UnityEngine.InputSystem.EnhancedTouch;
+using UnityEngine.InputSystem.Layouts;
 using UnityEngine.TestTools;
 using Touch = UnityEngine.InputSystem.EnhancedTouch.Touch;
 using TouchPhase = UnityEngine.InputSystem.TouchPhase;
@@ -64,6 +65,84 @@ public void TouchscreenAddedAndRemoved()
         Assert.IsFalse(touchscreen.added);
     }
 
+    [Test]
+    [Category("Device Simulator")]
+    public void ConflictingDevicesAreNotDisabledOnCreate()
+    {
+        var mouse = AddNativeMouse();
+        Assert.That(mouse.native, Is.True);
+
+        var plugin = new InputSystemPlugin();
+        plugin.OnCreate();
+
+        // Conflicting devices are only disabled once the Simulator gains focus, not on create.
+        Assert.That(mouse.enabled, Is.True);
+
+        plugin.OnDestroy();
+    }
+
+    [Test]
+    [Category("Device Simulator")]
+    public void ConflictingDeviceAddedWhileSimulatorFocused_IsDisabledThenReenabledOnDestroy()
+    {
+        var plugin = new InputSystemPlugin();
+        plugin.OnCreate();
+
+        // Simulate the Simulator window being focused (bypasses the panel-based OnUpdate).
+        plugin.SetConflictingDevicesDisabled(true);
+
+        var mouse = AddNativeMouse();
+
+        Assert.That(mouse.native, Is.True);
+        Assert.That(mouse.enabled, Is.False);   // disabled via the OnDeviceChange gate
+
+        plugin.OnDestroy();
+        Assert.That(mouse.enabled, Is.True);     // ReenableConflictingDevices restores it
+    }
+
+    [Test]
+    [Category("Device Simulator")]
+    public void ConflictingDevicesReenabledWhenSimulatorLosesFocus()
+    {
+        var mouse = AddNativeMouse();
+
+        var plugin = new InputSystemPlugin();
+        plugin.OnCreate();
+
+        plugin.SetConflictingDevicesDisabled(true);    // Simulator gained focus
+        Assert.That(mouse.enabled, Is.False);
+
+        plugin.SetConflictingDevicesDisabled(false);   // Simulator lost focus
+        Assert.That(mouse.enabled, Is.True);
+
+        plugin.OnDestroy();
+    }
+
+    [Test]
+    [Category("Device Simulator")]
+    public void ConflictingDeviceAddedWhileSimulatorNotFocused_StaysEnabled()
+    {
+        var plugin = new InputSystemPlugin();
+        plugin.OnCreate();
+        // m_ConflictingDevicesDisabled defaults to false (Simulator not focused).
+
+        var mouse = AddNativeMouse();
+
+        Assert.That(mouse.enabled, Is.True);
+
+        plugin.OnDestroy();
+    }
+
+    // Reports a native Mouse through the test runtime (device.native == true, which the plugin's
+    // disable logic requires) and returns the resolved device rather than relying on Mouse.current.
+    private Mouse AddNativeMouse()
+    {
+        var deviceId = runtime.ReportNewInputDevice(
+            new InputDeviceDescription { deviceClass = "Mouse", interfaceName = "Test" });
+        InputSystem.Update();
+        return (Mouse)InputSystem.GetDeviceById(deviceId);
+    }
+
     private TouchEvent CreateTouch(int touchId, Vector2 position, UnityEditor.DeviceSimulation.TouchPhase phase)
     {
         var touch = new TouchEvent();

Packages/com.unity.inputsystem/CHANGELOG.md

@@ -39,6 +39,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed `OnMouseUpAsButton` and `OnMouseUp` being dropped in Play mode when the Game view's focus changes between a press and its release on Unity 6000.5.0a8 and newer. The legacy `SendMouseEvents` pipeline is no longer driven from `InputUpdateType.Editor` updates, which read the editor state buffer (position (0,0), not pressed) and produced a spurious mouse release that cleared the press target.
 - Fixed Input Debugger window's incorrect name. It is now called 'Input Debugger' instead of 'Input Debug' [UUM-137124](https://jira.unity3d.com/browse/UUM-137124).
 - Fixed `PoseControl.isTracked` always returning false when read through non-optimized code paths (e.g. Input Debugger) due to `sizeInBits = 8` causing the value to be normalized as `1/255` instead of `1.0`.
+- Fixed the Device Simulator plugin keeping the real mouse and pen disabled while working in other Editor windows. Conflicting native `Mouse`/`Pen` devices are now only disabled while the Simulator window is focused and re-enabled as soon as focus moves elsewhere [UUM-145509](https://jira.unity3d.com/browse/UUM-145509).
 
 ### Changed
 

Packages/com.unity.inputsystem/InputSystem/Editor/DeviceSimulator/InputSystemPlugin.cs

@@ -2,8 +2,11 @@
 
 using System;
 using System.Collections.Generic;
+using UnityEditor;
 using UnityEditor.DeviceSimulation;
+using UnityEditor.UIElements;
 using UnityEngine.InputSystem.LowLevel;
+using UnityEngine.UIElements;
 
 namespace UnityEngine.InputSystem.Editor
 {
@@ -13,6 +16,9 @@
 
         private bool m_InputSystemEnabled;
         private bool m_Quitting;
+        private bool m_ConflictingDevicesDisabled;
+        private VisualElement m_RootElement;
+        private EditorWindow m_LastFocusedWindow;
         private List<InputDevice> m_DisabledDevices;
 
         public override string title => "Input System";
@@ -25,19 +31,16 @@
                 // Monitor whether the editor is quitting to avoid risking unsafe EnableDevice while quitting
                 UnityEditor.EditorApplication.quitting += OnQuitting;
 
+                // Poll the active window so conflicting devices are only disabled while the simulator is focused.
+                UnityEditor.EditorApplication.update += OnUpdate;
+
                 m_DisabledDevices = new List<InputDevice>();
 
                 // deviceSimulator is never null when the plugin is instantiated by a simulator window, but it can be null during unit tests
                 if (deviceSimulator != null)
                     deviceSimulator.touchScreenInput += OnTouchEvent;
                 InputSystem.onDeviceChange += OnDeviceChange;
 
-                // UGUI elements like a button don't get pressed when multiple pointers for example mouse and touchscreen are sending data at the same time
-                foreach (var device in InputSystem.devices)
-                {
-                    DisableConflictingDevice(device);
-                }
-
                 SimulatorTouchscreen = InputSystem.AddDevice<Touchscreen>("Device Simulator Touchscreen");
             }
         }
@@ -56,6 +59,72 @@
                 });
         }
 
+        public override VisualElement OnCreateUI()
+        {
+            m_RootElement = new VisualElement();
+            m_RootElement.Add(new HelpBox(
+                L10n.Tr("Manages Input System devices while the Simulator is focused."),
+                HelpBoxMessageType.Info));
+            return m_RootElement;
+        }
+
+        private void OnUpdate()
+        {
+            if (!EditorApplication.isPlaying)
+            {
+                if (m_ConflictingDevicesDisabled)
+                {
+                    SetConflictingDevicesDisabled(false);
+                    m_LastFocusedWindow = null;
+                }
+                return;
+            }
+
+            var focusedWindow = EditorWindow.focusedWindow;
+            if (focusedWindow == m_LastFocusedWindow)
+                return;
+            m_LastFocusedWindow = focusedWindow;
+
+            var simulatorFocused =
+                m_RootElement != null
+                && focusedWindow != null
+                && focusedWindow.rootVisualElement.panel == m_RootElement.panel;
+
+            SetConflictingDevicesDisabled(simulatorFocused);
+        }
+
+        // Exposed internally so tests can drive the focus transition without a live SimulatorWindow.
+        // OnUpdate itself can't run in a unit test: it needs play mode and a real panel to compare against.
+        internal void SetConflictingDevicesDisabled(bool disabled)
+        {
+            if (disabled == m_ConflictingDevicesDisabled)
+                return;
+
+            if (disabled)
+            {
+                // UGUI elements like a button don't get pressed when multiple pointers for example mouse and touchscreen are sending data at the same time
+                foreach (var device in InputSystem.devices)
+                    DisableConflictingDevice(device);
+            }
+            else
+            {
+                foreach (var device in m_DisabledDevices)
+                {
+                    // Note that m_Quitting is used here to mitigate the problem reported in issue tracker:
+                    // https://issuetracker.unity3d.com/product/unity/issues/guid/UUM-10774.
+                    // Enabling a device will call into IOCTL of backend which may be destroyed prior
+                    // to this callback on Unity version. This is not a fix for the actual problem
+                    // of shutdown order but a package fix to mitigate this problem.
+                    // The core problem with the destruction order was still there in Unity 6.5.
+                    if (device.added && !m_Quitting)
+                        InputSystem.EnableDevice(device);
+                }
+                m_DisabledDevices.Clear();
+            }
+
+            m_ConflictingDevicesDisabled = disabled;
+        }
+
         private void DisableConflictingDevice(InputDevice device)
         {
             if (device.native && (device is Mouse || device is Pen) && device.enabled)
@@ -67,6 +136,10 @@
 
         private void OnDeviceChange(InputDevice device, InputDeviceChange change)
         {
+            // Only disable newly added/reconnected devices while the simulator is the active window.
+            if (!m_ConflictingDevicesDisabled)
+                return;
+
             if (change == InputDeviceChange.Added || change == InputDeviceChange.Reconnected)
                 DisableConflictingDevice(device);
         }
@@ -100,20 +173,13 @@
                 InputSystem.onDeviceChange -= OnDeviceChange;
 
                 UnityEditor.EditorApplication.quitting -= OnQuitting;
+                UnityEditor.EditorApplication.update -= OnUpdate;
 
                 if (SimulatorTouchscreen != null)
                     InputSystem.RemoveDevice(SimulatorTouchscreen);
-                foreach (var device in m_DisabledDevices)
-                {
-                    // Note that m_Quitting is used here to mitigate the problem reported in issue tracker:
-                    // https://issuetracker.unity3d.com/product/unity/issues/guid/UUM-10774.
-                    // Enabling a device will call into IOCTL of backend which may be destroyed prior
-                    // to this callback on Unity version. This is not a fix for the actual problem
-                    // of shutdown order but a package fix to mitigate this problem.
-                    // The core problem with the destruction order was still there in Unity 6.5.
-                    if (device.added && !m_Quitting)
-                        InputSystem.EnableDevice(device);
-                }
+
+                SetConflictingDevicesDisabled(false);
+                m_RootElement = null;
             }
         }