// params: title, web, title, web, ...
static JTabbedPane showTabbedWebs(O... params) {
  O[] x = cloneObjectArray(params);
  for i over x: {
    Web web = castOpt(x[i], Web);
    if (web == null) continue;
    CirclesAndLines cal = webToCAL(web);
    Canvas canvas = cal.makeCanvas();
    x[i] = canvas;
    calAutoLayout(cal, canvas);
  }
  ret showTabs(x);
}