// x = names and components interleaving.
// or just components.
// or just names.
// also, you can pass a Collection containing the elements
svoid addTabs(JTabbedPane tabs, O... x) {
  if (tabs == null) null;
  O[] x = flattenToArray(x);
  int n = 0;
  for (int i = 0; i < l(x); i++) {
    ++n;
    
    // is it a component?
    O o = x[i];
    if (isComponentOrSwingable(o))
      addTab(tabs, "Tab " + n, wrap(o));
    else {
      // assume it's a tab name, optionally followed by a component
      S toolTip = "";
      
      // WithToolTip<S> is ok (WithToolTip<Component> not yet supported)
      if (o cast WithToolTip) {
        toolTip = o.toolTip();
        o = o!;
      }
      S name = str(or(o, "Tab " + n));
      Component c;
      if (isComponentOrSwingable(get(x, i+1)))
        c = wrap(get(x, ++i));
      else
        c = new JPanel;
      addTabWithToolTip(tabs, name, toolTip, wrap(c));
    }
  }
}