How to delete a nested tab group

The opposite of How to create nested Tab Groups. I can't delete a tab group in a folder
Something like this for two tab groups aaa at the root and in a dir_parent directory

  var tabGroups = DOpus.TabGroups;
  var tabGroupsDirL; // found dir by name
  for (var e = new Enumerator(tabGroups); !e.atEnd(); e.moveNext()) {
    var tg = e.item();
    if ((tg.folder) && (tg.name === "dir_parent")) {
      tabGroupsDirL = tg;    };}

  for (var e = new Enumerator(tabGroupsDirL); !e.atEnd(); e.moveNext()) {var tg = e.item();
    if ("aaa" === tg.name) {tabGroupsDirL.DeleteChild(tg);};
  }
  tabGroups.Save();

same thing without nesting works

  for (var e = new Enumerator(tabGroups); !e.atEnd(); e.moveNext()) {var tg = e.item();
    if ("aaa" === tg.name) {tabGroups.DeleteChild(tg);};
  }
  tabGroups.Save();

A fix for this will be in 13.14.1.