FIX: PlayerInput component is redrawn all the time when the notification mode is set to Invoke Unity events (#2166)

Author: K-Tone

Packages/com.unity.inputsystem/CHANGELOG.md

@@ -19,6 +19,7 @@ however, it has to be formatted properly to pass verification tests.
 - Fixed Input Actions code generation overwriting user files when the names happened to match. [ISXB-1257](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-1257)
 - Fixed Input Actions code generation using locale-dependent rules when lowercasing and uppercasing strings. [ISXB-1406]
 - Fixed an issue when providing JoinPlayer with a specific split screen index. [ISXB-897](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-897)
+- Fixed Inspector Window being refreshed all the time when a PlayerInput component is present with Invoke Unity Events nofication mode chosen [ISXB-1448](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-1448)
 - Fixed an issue where an action with a name containing a slash "/" could not be found via `InputActionAsset.FindAction(string,bool)`. [ISXB-1306](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-1306).
 
 ## [1.14.0] - 2025-03-20

Packages/com.unity.inputsystem/InputSystem/Plugins/PlayerInput/PlayerInputEditor.cs

@@ -417,17 +417,21 @@ private void OnNotificationBehaviorChange()
                 case PlayerNotifications.InvokeUnityEvents:
                 {
                     var playerInput = (PlayerInput)target;
-                    if (playerInput.m_DeviceLostEvent == null)
-                        playerInput.m_DeviceLostEvent = new PlayerInput.DeviceLostEvent();
-                    if (playerInput.m_DeviceRegainedEvent == null)
-                        playerInput.m_DeviceRegainedEvent = new PlayerInput.DeviceRegainedEvent();
-                    if (playerInput.m_ControlsChangedEvent == null)
-                        playerInput.m_ControlsChangedEvent = new PlayerInput.ControlsChangedEvent();
-                    serializedObject.Update();
-
-                    // Force action refresh.
-                    m_ActionAssetInitialized = false;
-                    Refresh();
+
+                    bool areEventsDirty = (playerInput.m_DeviceLostEvent == null) || (playerInput.m_DeviceRegainedEvent == null) || (playerInput.m_ControlsChangedEvent == null);
+
+                    playerInput.m_DeviceLostEvent ??= new PlayerInput.DeviceLostEvent();
+                    playerInput.m_DeviceRegainedEvent ??= new PlayerInput.DeviceRegainedEvent();
+                    playerInput.m_ControlsChangedEvent ??= new PlayerInput.ControlsChangedEvent();
+
+                    if (areEventsDirty)
+                    {
+                        serializedObject.Update();
+
+                        // Force action refresh.
+                        m_ActionAssetInitialized = false;
+                        Refresh();
+                    }
                     break;
                 }
             }