private void OnEnable()
        {
            s_Instance = this;

            titleContent = new GUIContent("Mesh Importer");
            minSize      = new Vector2(k_WindowWidth, k_WindowHeight);
            if (m_SourcePath == null || m_SourcePath.Length != k_MaxSubMeshCount)
            {
                m_SourcePath = new string[k_MaxSubMeshCount];
            }
        }
 private void OnDisable()
 {
     s_Instance = null;
 }