FIX: PlayerInput default ActionMap set to <None> is overwritten (#2170)

Author: ritamerkl

Packages/com.unity.inputsystem/CHANGELOG.md

@@ -22,6 +22,7 @@ however, it has to be formatted properly to pass verification tests.
 - 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).
 - Fixed Gamepad stick up/down inputs that were not recognized in WebGL. [ISXB-1090](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-1090)
+- Fixed PlayerInput component automatically switching away from the default ActionMap set to 'None'.
 
 ## [1.14.0] - 2025-03-20
 

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

@@ -551,7 +551,7 @@ void AddEntry(InputAction action, PlayerInput.ActionEvent actionEvent)
             var selectedDefaultActionMap = !string.IsNullOrEmpty(playerInput.defaultActionMap)
                 ? asset.FindActionMap(playerInput.defaultActionMap)
                 : null;
-            m_SelectedDefaultActionMap = asset.actionMaps.Count > 0 ? 1 : 0;
+            m_SelectedDefaultActionMap = (asset.actionMaps.Count > 0 && m_SelectedDefaultActionMap == -1) ? 1 : 0;
             var actionMaps = asset.actionMaps;
             m_ActionMapOptions = new GUIContent[actionMaps.Count + 1];
             m_ActionMapOptions[0] = new GUIContent(EditorGUIUtility.TrTextContent("<None>"));