public override void OnInspectorGUI()
    {
        DrawDefaultInspector();
        VideoContentManager targetManager = (VideoContentManager)target;

        if (GUILayout.Button("Get Display Columns"))
        {
            targetManager.SetDisplayColumnsVariable();
        }
        if (GUILayout.Button("Read Files From Path"))
        {
            targetManager.ReadFilesFromPath();
        }
        if (GUILayout.Button("Initialize Video Columns"))
        {
            targetManager.InitializeVideoColumns();
        }
    }
    void OnValidate()
    {
        VideoContentManager targetManager = (VideoContentManager)target;

        targetManager.InitializeVideoColumns();
    }