Scrollable panel group in scriptUI

Any suggestions on how to make this work properly?

The code like it is, the maxvlue of scrollbar shows nothing and my array of items (which has 50 elements) shows up to #40. (PS: if I change my array's length to 30, for example, all items are shown, but there is still blank space at the bottom).

Any help will be appreciated.

var array = new Array (50);
var w = new Window("dialog" , "Scroll test");
w.maximumSize.height = 300;
var p = w.add("panel" , undefined , "Scroll group");
p.margins.top = 20;
p.maximumSize.height = w.maximumSize.height-30;
var g = p.add("group");
g.orientation = "column";
g.alignChildren = "left";
g.alignment = ["fill","bottom"];

for (var i=0; i<array.length; i++) {
    g.add("statictext" , undefined , "Item " + (i+1));
    }

var scrollBar = p.add("scrollbar");
scrollBar.stepdelta = 10;
scrollBar.maximumSize.height = g.maximumSize.height;

scrollBar.onChanging = function () {
    g.location.y = -1 * this.value;
    }

w.onShow = function() {
    scrollBar.size.height = p.size.height-10;
    scrollBar.size.width = 22;
    scrollBar.location = [p.size.width-22, 0];
//~     scrollBar.maxvalue = g.size.height - p.size.height + 15;
    scrollBar.maxvalue = g.size.height + 15;
    };

w.show();