FIX: DefaultActionMap dropdown set to <None> by default (ISXB-1559)

Packages/com.unity.inputsystem/CHANGELOG.md

@@ -31,6 +31,7 @@ however, it has to be formatted properly to pass verification tests.
 - Fixed PlayerInput component automatically switching away from the default ActionMap set to 'None'.
 - Fixed a console error being shown when targeting visionOS builds in 2022.3.
 - Fixed a Tap Interaction issue with analog controls. The Tap interaction would keep re-starting after timeout. [ISXB-627](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-627)
+- Fixed the defaultActionMap dropdown in the PlayerInput component defaulting to <None> instead of the first ActionMap.
 
 ## [1.14.0] - 2025-03-20
 

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

@@ -80,9 +80,11 @@
             EditorGUI.BeginChangeCheck();
             EditorGUILayout.PropertyField(m_ActionsProperty);
             var actionsWereChanged = false;
-            if (EditorGUI.EndChangeCheck() || !m_ActionAssetInitialized || CheckIfActionAssetChanged())
+            var assetChanged = CheckIfActionAssetChanged();
+            // initialize the editor component if the asset has changed or if it has not been initialized yet
+            if (EditorGUI.EndChangeCheck() || !m_ActionAssetInitialized || assetChanged || m_ActionAssetInstanceID == 0)
             {
-                OnActionAssetChange();
+                InitializeEditorComponent(assetChanged);
                 actionsWereChanged = true;
             }
 
@@ -262,7 +264,8 @@
             if (m_ActionsProperty.objectReferenceValue != null)
             {
                 var assetInstanceID = m_ActionsProperty.objectReferenceValue.GetInstanceID();
-                bool result = assetInstanceID != m_ActionAssetInstanceID;
+                // if the m_ActionAssetInstanceID is 0 the PlayerInputEditor has not been initialized yet, but the asset did not change
+                bool result = assetInstanceID != m_ActionAssetInstanceID && m_ActionAssetInstanceID != 0;
                 m_ActionAssetInstanceID = (int)assetInstanceID;
                 return result;
             }
@@ -439,19 +442,21 @@
             m_NotificationBehaviorInitialized = true;
         }
 
-        private void OnActionAssetChange()
+        private void InitializeEditorComponent(bool assetChanged)
         {
             serializedObject.ApplyModifiedProperties();
             m_ActionAssetInitialized = true;
 
             var playerInput = (PlayerInput)target;
             var asset = (InputActionAsset)m_ActionsProperty.objectReferenceValue;
+
+            if (assetChanged)
+                m_SelectedDefaultActionMap = -1;
             if (asset == null)
             {
                 m_ControlSchemeOptions = null;
                 m_ActionMapOptions = null;
                 m_ActionNames = null;
-                m_SelectedDefaultActionMap = -1;
                 m_SelectedDefaultControlScheme = -1;
                 m_InvalidDefaultControlSchemeName = null;
                 return;