public static void OpenUI()
 {
     if (wnd == null)
     {
         wnd = GetWindow <VersionManagerGUI>();
         wnd.titleContent = new GUIContent("VFS Version Manager");
         wnd.minSize      = new Vector2(600, 400);
     }
     else
     {
         wnd.Show();
         wnd.Focus();
     }
 }
 private void OnDestroy()
 {
     wnd = null;
 }