void OnGUI()
    {
        GameObject mergerObject = GameObject.Find("Scene Merger");

        if (!mergerObject)
        {
            Debug.LogError("'Scene Merger' is not found");
            return;
        }

        SceneMerger merger = mergerObject.GetComponent <SceneMerger> ();

        if (GUILayout.Button("Load"))
        {
            ClearOverlay();
            PushSceneObjects();
            LoadScenesToOverlay(merger.mergeScenes);
            PopSceneObjects();
        }

        if (GUILayout.Button("Clean up"))
        {
            ClearOverlay();
        }
    }
    void OnGUI()
    {
        GameObject mergerObject = GameObject.Find("SceneMerger");

        if (!mergerObject)
        {
            return;
        }

        SceneMerger merger = mergerObject.GetComponent <SceneMerger> ();

        if (GUILayout.Button("Load"))
        {
            merger.ClearOverlay();
            merger.PushSceneObjects();
            merger.LoadScenesToOverlay();
            merger.PopSceneObjects();
        }

        if (GUILayout.Button("Clean up"))
        {
            merger.ClearOverlay();
        }
    }