private async Task CollapseAllNodes(){    await _treeView.CollapseAllAsync();}private async Task RadioButtonChanged(int rbValue){    Console.WriteLine($"Radio button changed to: {rbValue}");    await CollapseAllNodes();    // 11/9/2025 Delay fixes bug where ExpandToLevel fails    await Task.Delay(500);   //    <--- WHY IS THIS NECESSARY????    ExpandToLevel(TreeItems,0, rbValue);}private void ExpandToLevel(List<TreeItemData<ICD10DiagCode>> items, int currentLevel, int targetLevel){    if (items == null || currentLevel >= targetLevel)    {        return;    }    foreach (var item in items)    {        //_expandedItems.Add(item); // Add the current item to expanded        item.Expanded = true;        if (item.Children != null && item.Children.Any())        {            ExpandToLevel(item.Children, currentLevel + 1, targetLevel);        }    }}