Hi experts, 

I'm working on the tree load on demand feature. And till now, I can expand the first node successfully and the second level data appended to tree correctly. But I have no idea why I cannot expand the second level node. It does not give me an arrow to click... I paste my js code and asp.net code below, please help . Thanks in advance!!!

==============================================================================================

my js code:

var data = [
{
"ID": 1, "CountryName": "North America", "Countries": []
},
{
"ID": 2, "CountryName": "South America", "Countries": []

},
{
"ID": 3, "CountryName": "Europe", "Countries": []

}
];

$("#alextree").igTree({
dataSource: data, //JSON Array defined above
bindings: {
textKey: "CountryName",
valueKey: "ID",
childDataProperty: "Countries",
bindings: {
textKey: "CountryName",
valueKey: "ID"
}
},
dataSourceUrl: window.BAConfiguration.baseUrl + "/SessionReadOnly/TreeOnDemand",
loadOnDemand: true

});

===============================================================================

the TreeOnDemand action,

public class Country
{
public string CountryName { get; set; }
public int ID { get; set; }
public List<Country> Countries { get { return new List<Country>(); } }
}
public JsonResult TreeOnDemand(string path, string binding, int depth) {

List<Country> c = new List<Country>();
c.Add(new Country { ID = new Random().Next(), CountryName = "country" + new Random().Next() });
return Json(c, JsonRequestBehavior.AllowGet);
}