Fix for defaultActionMap dropdown set to first actionMap by default

Author: ritamerkl

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

@@ -80,9 +80,11 @@ public override void OnInspectorGUI()
             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 @@ bool CheckIfActionAssetChanged()
             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 @@ private void OnNotificationBehaviorChange()
             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;