DrawSceneEditor now has a single, non-branching undo check

This was done to balance out undo calls when no scene is selected from scene picker

UOP1_Project/Assets/Scripts/Editor/GameSceneEditor.cs

         var sceneName = gameSceneTarget.sceneName;
         EditorGUI.BeginChangeCheck();
         var selectedScene = sceneList.ToList().IndexOf(sceneName);
-        selectedScene = EditorGUILayout.Popup("Scene", selectedScene, sceneList);
-        if (selectedScene > -1)
+
+        if (selectedScene < 0)
-            if (EditorGUI.EndChangeCheck())
-            {
-                Undo.RecordObject(target, "Changed selected scene");
-                gameSceneTarget.sceneName = sceneList[selectedScene];
-                MarkAllDirty();
-            }
+            EditorGUILayout.HelpBox(noScenesWarning, MessageType.Warning);
-        else
+        
+        selectedScene = EditorGUILayout.Popup("Scene", selectedScene, sceneList);
+        if (EditorGUI.EndChangeCheck())
-            EditorGUILayout.HelpBox(noScenesWarning, MessageType.Warning);
+            Undo.RecordObject(target, "Changed selected scene");
+            gameSceneTarget.sceneName = sceneList[selectedScene];
+            MarkAllDirty();
         }
     }