Error: can't expand a TreePanel with two levels nodes

[adabo]

I have two problems with a tree node.I used a tree panel to display a 2-level tree of privileges with check boxes at the leaf nodes .
the first problem: when I expanded the first node it is expanded fine but when i expanded the second node it wasn't. without any javascript error
the second problem: when I expand the first node and click on check box of leaf node it didn't checked but the following checkbox is checked.


after more clicks on check boxes, javascript error raised

Unhandled exception at line 1476, column 46 in http://XXX/extnet/extnet-all-js/ext.axd?v=31282
JavaScript runtime error: Unable to get property 'get' of undefined or null reference

with debuging i found record is null in this method
onCheckChange: function(record) {
var checked = record.get('checked');
if (Ext.isBoolean(checked)) {
checked = !checked;
record.set('checked', checked);
this.fireEvent('checkchange', record, checked);
}
}


I used the ext.net v2.5.1 downloaded from ext,net site because I faced [property 'isCollapsedPlaceholder' of undefined or null reference] proplem that solved in this thread http://forums.ext.net/showthread.php...null-reference


View Page:

@model Ext.Net.Node
@{
    ViewBag.Title = "Group privileges";
}
@(Html.X().ResourceManager().ScriptMode(Ext.Net.ScriptMode.Development))

@using (Html.BeginForm())
{
    @Html.AntiForgeryToken()
    <div class="form-horizontal">     
        <div class="back-link">
            @Html.ActionLink("Back to List", "Index", null, new { @class = "pull-right" })
        </div>      
    </div>    
<div style="padding-top: 30px;">

        @( Html.X().TreePanel().ID("TreePanel").Border(false)
                .DisplayField("text") //Kp_Naziv
                .Height(400).Width(500).UseArrows(false).Border(false).AutoScroll(true).Animate(true).RootVisible(false)
                .Root(Model)
        )
</div>
    
 <div class="form-horizontal">   
    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            @Html.ActionLink("Back to Groups", "Index", null, new { @class = "btn btn-default" })
            <input type="submit" value="Save" class="btn btn-default" onclick="return Save()" />
        </div>
    </div>
</div>
}

CS code: Action

 public ActionResult Privileges(int id)
        {
            ViewBag.GroupID = id;
            Ext.Net.Node rootNode = new Node { NodeID = "0", Text = "Root", Checked = false, Icon = Icon.Folder, Leaf = false,Expanded=true}; 
            var lists = db.Lists.ToList();
            var groupColumn = db.GroupListItems.Where(o => o.GroupID == id);
            foreach (var list in lists)
            {
                Ext.Net.Node node = new Node { NodeID = list.ListID.ToString(), Text = list.ListName, Icon = Icon.Table, Leaf = false,Expanded=false };
                var columns = list.ListItems;
                foreach (var column in columns)
                {
                    node.Children.Add(new Node { NodeID = column.ListItemID.ToString(), Text = column.ItemID, Icon = Icon.TableColumn, Leaf = true, Checked = groupColumn.Any(o => o.ListItemID == column.ListItemID) });
                }

                rootNode.Children.Add(node);
            }          
            return View("Privileges", rootNode);
        }

[adabo]

thank you, I reached to the error. there are more nodes have the same id number.