protected override void OnEnable()
        {
            if (preview == null)
            {
                preview = CreateInstance <Texture3DPreview>();
            }

            base.OnEnable();
            preview.OnEnable();
        }
        protected virtual void OnEnable()
        {
            m_WrapU      = serializedObject.FindProperty("m_TextureSettings.m_WrapU");
            m_WrapV      = serializedObject.FindProperty("m_TextureSettings.m_WrapV");
            m_WrapW      = serializedObject.FindProperty("m_TextureSettings.m_WrapW");
            m_FilterMode = serializedObject.FindProperty("m_TextureSettings.m_FilterMode");
            m_Aniso      = serializedObject.FindProperty("m_TextureSettings.m_Aniso");

            RecordTextureMipLevels();

            SetMipLevelDefaultForVT();

            m_Texture3DPreview         = CreateInstance <Texture3DPreview>();
            m_Texture3DPreview.Texture = target as Texture;
            m_Texture3DPreview.OnEnable();
        }