Hi, we have the same problem, so after some digging I come with this workaround (not perfect but at least combo is "disabled"). If you still need it - 

style

 .WC4-TB-N:disabled{        color:gray;
    }

 and some javascript on every page (in our base .js file)

$(function () {
            var orig_ShowResultBox = WC40Engine.ShowResultBox;
            WC40Engine.ShowResultBox = function (a, b, c) {
                if (a.TextObj.disabled)
                    return;

                orig_ShowResultBox(a, b, c);
            }


            WC40Engine.OnMouseOver = function (a) {
                if (!a.IsTextObjFocused && !a.IsInOver) {
                  
                    /*
                    !!! this is not working on DIV element !!!
                    if (IS.moz && a.FrameObj.getAttribute("disabled") == "disabled") {
                        return
                    }*/

                    if (a.TextObj.disabled) {
                        return;
                    }
                    a.LayoutSettings.FrameStyle.SetToOver();
                    a.LayoutSettings.TextBoxStyle.SetToOver();
                    a.LayoutSettings.DropDownStyle.SetToOver();
                    if (a.LayoutSettings.RoundCorner) {
                        WC40Engine.FormatRoundCorner(a)
                    }
                    if (a.LayoutSettings.EnableAnimation) {
                        WC40Engine.AnimateBackground(a, "Display")
                    }
                    if (a.HasTextBoxBorder) {
                        WC40Engine.SetupSpecialTextBoxBorder(a)
                    }
                    a.IsInOver = true
                }
            };


        });

Hi,

thanks for your time, you are right, in our scenario I can keep PopulateOnDemand = false for this nodes and I combine our two scenarios... But I can still do in ASP:TreeView this (basicaly ExpandToNode / ExpandToNodes functionality)

protected void TreeView1_TreeNodePopulate(object sender, TreeNodeEventArgs e)    {
        TreeNode n = new TreeNode();
        n.PopulateOnDemand = true;
        e.Node.ChildNodes.Add(n);
        if (...) // condition for nodes i want expand
            n.Expand(); // it calls resursively by treeview
    }

and it expand tree on server and send all nodes to client in 1 request (ExpandToNodes functionality). This doesnt work with WebTreeView. I can call n.Expand() on WebTreeView1_InitializeChildNodes but nothing happend - i know its not asp:TreeView, just asking if there is better way than "clicking" with javascript on nodes and generate many requests.

Another thing i notice is if I expand node (populateOnDemand) and it has no child the "plus" button didnt hide and also clientside event OnNodeExpand is not called (but this is maybe OK, nothing expanded)

Thanks