/**
         * <summary>Adds a new scene as a sub-scene, without affecting any other open scenes.</summary>
         * <param name = "subSceneIndex">The index of the new scene to open</param>
         * <returns>True if the scene was succesfully added</returns>
         */
        public bool AddSubScene(int subSceneIndex)
        {
            // Check if scene is already open
            if (subSceneIndex == CurrentSceneIndex)
            {
                return(false);
            }

            foreach (SubScene subScene in subScenes)
            {
                if (subScene.SceneIndex == subSceneIndex)
                {
                    return(false);
                }
            }

            SceneInfo subSceneInfo = GetSceneInfo(subSceneIndex);

            if (subSceneInfo != null)
            {
                subSceneInfo.Add();
                return(true);
            }

            return(false);
        }