// params: title, web, title, web, ...
static JTabbedPane showTabbedWebs(fO... params) {
  ret swing(func -> JTabbedPane {
    new L out;
    for (O o : params) {
      Web web = castOpt(o, Web);
      if (web == null) { out.add(o); continue; }
      CirclesAndLines cal = webToCAL(web);
      Canvas canvas = cal.makeCanvas();
      if (!isString(last(out)))
        out.add(unnull(cal.title));
      out.add(calAutoLayout2(cal, canvas));
    }
    ret showTabs(toObjectArray(out));
  });
}