Hello,

I am really glad that the DropDownTree component may be available in a few months, and I will definitely use it as soon as it is available. However, I still need to mitigate the problem I have in the meantime. I downloaded the source code of Telerik UI for Blazor 6.0.2 and the following changes in GroupHeaderItem.razor.cs seem to fix the issue:

    [HideFromApiRef]
    public partial class GroupHeaderItem : GroupItemBase, IDisposable
    {
        private readonly List<string> ObservableParameters = new List<string>()
        {
            nameof(Groups)
        };

        private bool _hasParameterChanged;

        ...

        public override async Task SetParametersAsync(ParameterView parameters)
        {
            _hasParameterChanged = parameters.HasAnyParameterChanged(this, ObservableParameters);

            await base.SetParametersAsync(parameters);
        }

        protected override void OnParametersSet()
        {
            if (_hasParameterChanged)
            {
                Group = Groups?.FirstOrDefault();
            }

            base.OnParametersSet();
        }

        ...

        [JSInvokable]
        [HideFromApiRef]
        public void CurrentGroupChanged(int index)
        {
            var restrictedIndex = index.Restrict(0, Groups.Count() - 1);

            ...

        }
    }

Hi,

I was hoping this problem would be resolved quickly as it does not seem that difficult to fix. In the meantime, we released our product with this component last week, and our customers are already complaining. Since the incorrect category is displayed, our users believe the search feature does not work at all and instead of using it they believe they have to scroll through our very long list of options and they are very annoyed.

If the fix is not that difficult, please prioritize this.

Thank you.