vertical scrollbar does not work in a nested dialog

In Adobe Illustrator CC 2014 Win 7 and Mac OS X 10.8

function dropdown2(win_location, win_width, h50, list2) {    var ww = new Window ("dialog");    var g = ww.add ("group");    var panel = g.add("panel", [0, 0, 300, 200]);    var sbar = g.add ("scrollbar", [0, 0, 20, 200]);    ww.show();
}

var w = new Window ("dialog");
w.add("button", undefined, "asdads").onClick = function () {
  dropdown2([200, 200], 200, 50, ["asdaf", "asdaf", "asdaf", "asdaf" ]); };
w.show();