DropdownButton closes content when clicking away

@inject IJSRuntime JSRuntime

@* Do not show "Export as" item in the popup *@
<style>
    .custom-popup-class .k-list-ul .k-list-item:nth-child(1) {
        display: none;
    }
</style>
<TelerikDropDownList Data="@Items"
                     OnOpen="OnDropDownListPopupOpen"
                     OnClose="@OnDropDownListPopupClose"
                     ValueField="@nameof(ItemDescriptor.ItemId)"
                     TextField="@nameof(ItemDescriptor.ItemText)"
                     Value="@DropDownListValue"
                     ValueChanged="@( (int selectedValue) => OnDropDownValueChanged(selectedValue) )"
                     Width="315px">
    <DropDownListSettings>
        <DropDownListPopupSettings Class="custom-popup-class" Height="auto" />
    </DropDownListSettings>
    <ValueTemplate>
        <div style="padding-right:3px">
        </div>
        @context.ItemText
    </ValueTemplate>
    <ItemTemplate>

        <div style="width: 30%; margin: 0 auto;" >
            <TelerikPanelBar Data="@Data" @bind-ExpandedItems="@ExpandedItems">
                <PanelBarBindings>
                    <PanelBarBinding Level="0">
                        <ContentTemplate Context="panelBarContext">
                            <div @onclick="@(ClickInputHandler)">
                                <TelerikTextBox @ref="@TextBoxRef" @bind-Value="@MyValue"
                                                Placeholder="Placeholder...">
                                </TelerikTextBox>

                            </div>
                        </ContentTemplate>
                    </PanelBarBinding>
                </PanelBarBindings>
            </TelerikPanelBar>
        </div>

    </ItemTemplate>
</TelerikDropDownList>

<script type="text/javascript">
    function removeFocus() {
        var element = document.querySelector(".k-dropdownlist");
        if (element) {
            element.blur();
        }
    }
</script>

@code {
    private TelerikTextBox TextBoxRef { get; set; }
    private bool TextBoxFocused { get; set; }

    private async Task ClickInputHandler()
    {
        await JSRuntime.InvokeVoidAsync("removeFocus");
        await TextBoxRef.FocusAsync();
        TextBoxFocused = true;
    }

    public class TreeItem
    {
        public int Id { get; set; }
        public string Text { get; set; }
        public bool Disabled { get; set; }
        public IEnumerable<TreeItem> Items { get; set; }
    }
    public IEnumerable<TreeItem> Data { get; set; }
    public IEnumerable<object> ExpandedItems { get; set; }

    private void LoadFlatData()
    {
        // TODO: Move to hierarchical data
        List<TreeItem> items = new List<TreeItem>();
        items.Add(new TreeItem() { Id = 0, Text = "My Teammates" });
        Data = items;
        ExpandedItems = new List<object> { items.First() };
    }
    private int DropDownListValue { get; set; }
    private bool isPopupOpen { get; set; }
    public string MyValue { get; set; } = "test";
    protected override void OnInitialized()
    {
        LoadFlatData();
        //always keep the "Export as" selected
        DropDownListValue = 1;
    }
    private void OnDropDownValueChanged(int selectedValue)
    {
        //get the selected item but do not update the viewmodel, so the text "Export as" is always visible
        var selectedItem = Items.FirstOrDefault(x => x.ItemId == selectedValue);
        Console.WriteLine($"The user selected export as: {selectedItem.ItemText}");
    }
    private void OnDropDownListPopupOpen(DropDownListOpenEventArgs args)
    {
        isPopupOpen = true;
        TextBoxFocused = true;
    }
    private async Task OnDropDownListPopupClose(DropDownListCloseEventArgs args)
    {
        isPopupOpen = true;

        if (TextBoxFocused)
        {
            args.IsCancelled = true;
            TextBoxFocused = false;
        }
    }
    private List<ItemDescriptor> Items { get; set; } = new List<ItemDescriptor>()
    {
        new ItemDescriptor(){ ItemId = 1, ItemText = "Export as", Icon = SvgIcon.Download},
        new ItemDescriptor(){ ItemId = 2, ItemText = "xlsx", Icon = SvgIcon.FileExcel},

    };
    public class ItemDescriptor
    {
        public int ItemId { get; set; }
        public string ItemText { get; set; }
        public ISvgIcon Icon { get; set; }
    }
}