added 'unload existing' flag to loading individual scene configs so you can load a set of scenes additively instead of replacing all existing scenes. also replaced the defaultinspector with a custom inspector for editing the scene configs

com.unity.film-tv.toolbox/Editor/MultiScene/MultiSceneLoaderEditor.cs

@@ -1,5 +1,7 @@
 using UnityEngine;
 using UnityEditor;
+using UnityEditor.SceneManagement;
+using System.Collections.Generic;
 
 namespace Unity.FilmTV.Toolbox.MultiScene
 {
@@ -9,7 +11,9 @@ namespace Unity.FilmTV.Toolbox.MultiScene
     [CustomEditor(typeof(MultiSceneLoader))]
 	public class MultiSceneLoaderEditor : Editor
 	{
-		public override void OnInspectorGUI()
+        public Dictionary<SceneConfig, bool> foldoutState = new Dictionary<SceneConfig, bool>();
+
+        public override void OnInspectorGUI()
 		{
 			var sceneConfig = (MultiSceneLoader)target;
 
@@ -20,7 +24,76 @@ namespace Unity.FilmTV.Toolbox.MultiScene
 
                 GUILayout.Label("Allows you to define sets of scenes that can be loaded either as one 'set' or individually as desired. Useful for defining subsets of a project that different team members can work on independently.", EditorStyles.wordWrappedLabel);
 
-                DrawDefaultInspector(); // TODO: make a proper inspector for the configs so I don't need to use the default inspector
+                GUILayout.Space(15f);
+
+                GUILayout.Label("Config List", EditorStyles.boldLabel);
+                for( var j = 0; j < sceneConfig.config.Count; j++)
+                {
+                    var entry = sceneConfig.config[j];
+                    if ( foldoutState.ContainsKey( entry))
+                    {
+                        foldoutState[entry] = EditorGUILayout.Foldout(foldoutState[entry], entry.name);
+                    }
+                    else
+                    {
+                        foldoutState.Add(entry, false);
+                        foldoutState[entry] = EditorGUILayout.Foldout(foldoutState[entry], entry.name);
+                    }
+
+                    if( foldoutState[entry])
+                    {
+                        GUILayout.BeginHorizontal();
+                        {
+                            GUILayout.Space(10f);
+                            GUILayout.BeginVertical();
+                            {
+                                GUILayout.BeginHorizontal();
+                                {
+                                    GUILayout.Label("Config name: ", GUILayout.Width(120f));
+                                    entry.name = GUILayout.TextField(entry.name);
+                                }
+                                GUILayout.EndHorizontal();
+                                // scene list
+                                for (var i = 0; i < entry.sceneList.Count; i++)
+                                {
+                                    GUILayout.BeginHorizontal();
+                                    {
+                                        entry.sceneList[i] = EditorGUILayout.ObjectField("Scene:", entry.sceneList[i], typeof(Object), false);
+                                        if (GUILayout.Button("-", GUILayout.Width(35f)))
+                                        {
+                                            entry.sceneList.Remove(entry.sceneList[i]);
+                                        }
+                                    }
+                                    GUILayout.EndHorizontal();
+                                }
+
+                                if (GUILayout.Button("Add New Scene"))
+                                {
+                                    entry.sceneList.Add(new Object());
+                                }
+                            }
+                            GUILayout.EndVertical();
+                        }
+                        GUILayout.EndHorizontal();
+
+                        GUILayout.Space(15f);
+                        if( GUILayout.Button("Remove Config"))
+                        {
+                            sceneConfig.config.Remove(entry);
+                            foldoutState.Remove(entry);
+                        }
+                    }
+                }
+                if( GUILayout.Button("Add new Config"))
+                {
+                    var newConfig = new SceneConfig()
+                    {
+                        name = "New Config"
+                    };
+                    sceneConfig.config.Add(newConfig);
+                }
+
+                //DrawDefaultInspector(); // TODO: make a proper inspector for the configs so I don't need to use the default inspector
 
                 EditorGUILayout.Space();
                 GUILayout.Label("Load All Scenes", EditorStyles.boldLabel);
@@ -37,7 +110,7 @@ namespace Unity.FilmTV.Toolbox.MultiScene
                 {
                     EditorGUILayout.Space();
                     if (GUILayout.Button("Load " + entry.name + " Scenes", GUILayout.MinHeight(100), GUILayout.Height(50)))
-                        sceneConfig.LoadSceneConfig(entry);
+                        sceneConfig.LoadSceneConfig(entry, true);
                     GUILayout.Label("Loads ONLY the scenes defined in " + entry.name + ".", EditorStyles.wordWrappedLabel);
                 }
             }

com.unity.film-tv.toolbox/Runtime/MultiScene/MultiSceneLoader.cs

@@ -75,14 +75,15 @@ namespace Unity.FilmTV.Toolbox.MultiScene
 		/// <summary>
 		/// Load a specific scene config
 		/// </summary>
-		public void LoadSceneConfig( SceneConfig config)
+		public void LoadSceneConfig( SceneConfig config, bool unloadExisting)
 		{
+			
 			for( int i = 0; i < config.sceneList.Count; i++)
 			{
 				if (i == 0)
 				{
-					// load the first scene in single mode
-					LoadScene(config.sceneList[i], false);
+					// if we need to unload existing, then load the first in single mode, otherwise everything is additive
+					LoadScene(config.sceneList[i], !unloadExisting);
 				}
 				else
 				{

com.unity.film-tv.toolbox/Samples/MultiScene/RuntimeLoadSample/TestRuntimeLoader.cs

@@ -44,12 +44,24 @@ namespace Unity.FilmTV.Toolbox.MultiScene.Samples
             {
                 Debug.Log("Loading scenes from config : " + thisConfig.name);
                 yield return new WaitForSeconds(1);
-                sceneConfig.LoadSceneConfig(thisConfig);
+                sceneConfig.LoadSceneConfig(thisConfig, true);
                 Debug.Log("Load  scenes from config : " + thisConfig.name + " - COMPLETE");
                 yield return new WaitForSeconds(2);
             }
 
-            Debug.Log("Load individual scene config - COMPLETE");
+            Debug.Log("Loading individual scene configs without unloading existing");
+
+            yield return new WaitForSeconds(1);
+            foreach (var thisConfig in sceneConfig.config)
+            {
+                Debug.Log("Loading scenes from config : " + thisConfig.name);
+                yield return new WaitForSeconds(1);
+                sceneConfig.LoadSceneConfig(thisConfig, false);
+                Debug.Log("Load  scenes from config : " + thisConfig.name + " - COMPLETE");
+                yield return new WaitForSeconds(2);
+            }
+            Debug.Log("Load individual scene config without unloading - COMPLETE");
+
             yield return new WaitForSeconds(1);
             Debug.Log("Test Runtime Scene loading - COMPLETE");
             yield return new WaitForSeconds(2);