mudblazor expand and and selected values not working

Hello I'm kinda new at mudblazor and I don't know how to manage with expand and show selected values. It shows the feature that I've waited and I can see the child features because expand button created but when I click expand button nothing happens. also when I click a feature I can't see it on selected values part.

@page "/featurepage"@using ProtaTestTrack2.Helpers@using ProtaTestTrack2.Services@using MudBlazor<MudTreeView Items="TreeItems" MultiSelection="false" SelectedValueChanged="FeatureChanged" @bind-ActivatedValue="ActivatedValue" @bind-SelectedValues="SelectedValues" Dense><ItemTemplate Context="item"><MudTreeViewItem @bind-Expanded="@item.IsExpanded" Items="@item.TreeItems" Value="@item"                        Icon="@item.Icon" Text="@item.Title" EndText="@item.Number?.ToString()" EndTextTypo="@Typo.caption"><BodyContent><MudText Style="justify-self: start;"><MudHighlighter Text="@context.Text" /></MudText></BodyContent></MudTreeViewItem></ItemTemplate></MudTreeView><MudText Style="width: 100%" Typo="@Typo.subtitle2">Selected Feature: @_ActivatedValue?.Title</MudText>@code {private int myVar;public int MyProperty{    get { return myVar; }    set { myVar = value; }}[Inject]FeatureService featureService { get; set; }private TreeItemData _ActivatedValue;[Parameter]public TreeItemData ActivatedValue { get    {        return _ActivatedValue;    } set    {        _ActivatedValue = value;        FeatureChanged.InvokeAsync(value);    }}[Parameter]public EventCallback<TreeItemData> FeatureChanged { get; set; }[Parameter]public HashSet<TreeItemData> SelectedValues { get; set; } = new HashSet<TreeItemData>();private HashSet<TreeItemData> TreeItems { get; set; } = new HashSet<TreeItemData>();protected override async Task OnInitializedAsync(){    var pop = await PopulateTree();}public async Task<bool> PopulateTree(){    //<https://github.com/MudBlazor/MudBlazor/discussions/7899>    // todo cache this features    var features = await featureService.GetAllFeaturesAsync();    var treehelper = new Helpers.TreeviewHelper(features);    treehelper.BuildTree();    TreeItems = treehelper.TreeItems;    StateHasChanged();    return true;}}

I tried to add render mode at app.razor but didn't work as well.