LoadGroupsOnDemand = true;
GridData = result;
GridRef.SetStateAsync(GridRef.GetState());

LoadGroupsOnDemand = true;
GridRef.LoadGroupsOnDemand = LoadGroupsOnDemand;
GridData = result;
GridRef.SetStateAsync(GridRef.GetState());

<TelerikGrid Id="@(Utility.CleanCssId("CrewGrid"))"
                 DetailTemplate="GridDetailTemplate"
                 EnableLoaderContainer="@ShowLoading"
                 Groupable="false"
                 Height="100%"
                 OnRead="@OnGridRead"
                 OnStateChanged="@OnGridStateChanged"
                 OnStateInit="@OnGridStateInit"
                 Pageable="true"
                 PageSize="@PageSize"
                 PageSizeChanged="@OnGridPageSizeChanged"
                 Reorderable="IsLargeScreen"
                 Resizable="IsLargeScreen"
                 SelectionMode="GridSelectionMode.Single"
                 ShowColumnMenu="IsLargeScreen"
                 Size="@GetGridSize"
                 Sortable="true"
                 SortMode="SortMode.Multiple"
                 TItem="CrewListItem"
                 @ref="Grid"
                 @bind-SelectedItems="@SelectedItems"
                 OnRowRender="OnRowRender">
    <NoDataTemplate>
        <strong>@RecordsMessage</strong>
    </NoDataTemplate>
    <GridSettings>
        <GridColumnMenuSettings Lockable="false" FilterMode="ColumnMenuFilterMode.None" />
        <GridPagerSettings InputType="PagerInputType.Buttons" PageSizes="@PageSizes" ButtonCount="5" Adaptive="false" Position="PagerPosition.Bottom" />
    </GridSettings>
    <GridColumns>
        <GridColumn Field="@nameof(CrewListItem.Color)"
                    Width="@(IsLargeScreen ? "40px" : "50px")"
                    Resizable="false"
                    ShowColumnMenu="false"
                    Groupable="false"
                    ShowColumnChooser="false"
                    Sortable="false"
                    HeaderClass="k-text-transparent"
                    OnCellRender="OnGridCellRender">
            <Template>
                @{
                    var item = (CrewListItem)context;
                    <M360ListColumnColor Color="@item.Color" IsLargeScreen="IsLargeScreen" />
                }
            </Template>
        </GridColumn>
        <GridColumn Field="@nameof(CrewListItem.Name)" Title="@TMessages.Crew" OnCellRender="OnGridCellRender" VisibleInColumnChooser="false">
            <Template>
                @{
                    var item = (CrewListItem)context;
                    <div class="k-d-flex k-h-full @(IsLargeScreen ? "k-align-items-stretch" : "k-align-items-center")">
                        <M360ListColumnLink Url="@string.Concat("crew/", item.Id)" Text="@item.Name" EntityType="Crew" IsPrimary="true" />
                    </div>
                }
            </Template>
        </GridColumn>
        <GridColumn Field="@nameof(CrewListItem.DivisionsJson)" Title="Division(s)" Sortable="true" Visible="IsLargeScreen" OnCellRender="OnGridCellRender">
            <Template>
                @{
                    var item = (CrewListItem)context;
                    <M360ListColumnList Items="@item.Divisions.ToList()" />
                }
            </Template>
        </GridColumn>
         .
         .
         .
    </GridColumns>
</TelerikGrid>

<tbody class="k-table-tbody" role="rowgroup">
  <tr
    role="row"
    class="k-master-row k-table-row k-alt k-table-alt-row"
    data-render-row-index="0"
    aria-rowindex="1"
  >
    . . .
  </tr>
  <tr
    role="row"
    class="k-master-row k-table-row k-alt k-table-alt-row"
    data-render-row-index="1"
    aria-rowindex="3"
  >
    . . .
  </tr>
  <tr
    role="row"
    class="k-master-row k-table-row k-alt k-table-alt-row"
    data-render-row-index="2"
    aria-rowindex="5"
  >
    . . .
  </tr>
  . . .
</tbody>

@using Telerik.DataSource
@using Telerik.DataSource.Extensions

Scroll through the groups or expand them to load their data on demand

<TelerikGrid TItem="@object"
             LoadGroupsOnDemand="true"
             Groupable="true"
             OnStateInit="@((GridStateEventArgs<object> args) => OnStateInitHandler(args))"
             OnRead="@ReadItems"
             ScrollMode="@GridScrollMode.Virtual" PageSize="20" RowHeight="60"
             Navigable="true" Sortable="true" FilterMode="@GridFilterMode.FilterRow" Height="600px">
    <GridColumns>
        <GridColumn Field="@nameof(Employee.Name)" FieldType="@typeof(string)" Groupable="false" />
        <GridColumn Field="@nameof(Employee.Team)" FieldType="@typeof(string)" Title="Team" />
        <GridColumn Field="@nameof(Employee.Salary)" FieldType="@typeof(decimal)" Groupable="false" />
        <GridColumn Field="@nameof(Employee.IsOnLeave)" FieldType="@typeof(bool)" Title="On Vacation" />
    </GridColumns>
</TelerikGrid>

@code {
    List<object> GridData { get; set; }

    protected async Task ReadItems(GridReadEventArgs args)
    {
        // sample data retrieval, see comments in the service mimic class below
        DataEnvelope<Employee> result = await MyService.GetData(args.Request);

        if (args.Request.Groups.Count > 0)
        {
            args.Data = result.GroupedData.Cast<object>().ToList();
        }
        else
        {
            args.Data = result.CurrentPageData.Cast<object>().ToList();
        }

        args.Total = result.TotalItemCount;
    }

    void OnStateInitHandler(GridStateEventArgs<object> args)
    {
        // set initial grouping
        GridState<object> desiredState = new GridState<object>()
        {
            GroupDescriptors = new List<GroupDescriptor>()
            {
                new GroupDescriptor()
                {
                    Member = "Team",
                    MemberType = typeof(string)
                },
                new GroupDescriptor()
                {
                    Member = "IsOnLeave",
                    MemberType = typeof(bool)
                }
            }
        };

        args.GridState = desiredState;
    }

    public class Employee
    {
        public int EmployeeId { get; set; }
        public string Name { get; set; }
        public string? Team { get; set; }
        public bool IsOnLeave { get; set; }
        public decimal Salary { get; set; }
    }

    public class DataEnvelope<T>
    {
        public List<AggregateFunctionsGroup> GroupedData { get; set; }
        public List<T> CurrentPageData { get; set; }
        public int TotalItemCount { get; set; }
    }

    public static class MyService
    {
        private static List<Employee> SourceData { get; set; }
        public static async Task<DataEnvelope<Employee>> GetData(DataSourceRequest request)
        {
            if (SourceData == null)
            {
                SourceData = new List<Employee>();
                var rand = new Random();
                for (int i = 1; i <= 3; i++)
                {
                    SourceData.Add(new Employee()
                    {
                        EmployeeId = i,
                        Name = "Employee " + i.ToString(),
                        Team = "Team " + i % 100,
                        IsOnLeave = i % 3 == 0,
                        Salary = rand.Next(1000, 5000)
                    });
                }
                SourceData.Add(new Employee()
                    {
                        EmployeeId = 3,
                        Name = "Employee " + 3.ToString(),
                        Team = null,
                        IsOnLeave = 3 % 3 == 0,
                        Salary = rand.Next(1000, 5000)
                    });
            }

            await Task.Delay(500);// deliberate delay to showcase async operations, remove in a real app

            // retrieve data as needed, you can find more examples and runnable projects here
            // https://github.com/telerik/blazor-ui/tree/master/grid/datasourcerequest-on-server
            var datasourceResult = SourceData.ToDataSourceResult(request);

            DataEnvelope<Employee> dataToReturn;

            if (request.Groups.Count > 0)
            {
                dataToReturn = new DataEnvelope<Employee>
                {
                    GroupedData = datasourceResult.Data.Cast<AggregateFunctionsGroup>().ToList(),
                    TotalItemCount = datasourceResult.Total
                };
            }
            else
            {
                dataToReturn = new DataEnvelope<Employee>
                {
                    CurrentPageData = datasourceResult.Data.Cast<Employee>().ToList(),
                    TotalItemCount = datasourceResult.Total
                };
            }

            return await Task.FromResult(dataToReturn);
        }
    }
}

    <TelerikTextBox>
        <TextBoxPrefixTemplate>
            First name
        </TextBoxPrefixTemplate>
    </TelerikTextBox>

The following code successfully renders the pdf viewer when the edit form is commented out, but when indside the pdf viewer it fails to render and gives the following error:
"Telerik.Blazor.Components.TelerikComboBox`2[Telerik.Blazor.Components.PdfViewer.Models.PdfViewerZoomLevelDescriptor,System.String] requires a value for the 'ValueExpression' ValueExpression is provided automatically when using 'bind-Value'.See more at https://docs.telerik.com/blazor-ui/knowledge-base/requires-valueexpression ."
 
 
@page "/pdfBug"

@* <EditForm Model="_fakeContext"> *@
    <TelerikPdfViewer Data="@PdfSource"
                      OnDownload="@OnPdfDownload"
                      Height="600px"></TelerikPdfViewer>
@* </EditForm> *@

@code {
    private byte[] PdfSource { get; set; }

    private async Task OnPdfDownload(PdfViewerDownloadEventArgs args)
    {
        args.FileName = "PDF-Viewer-Download";
    }

    protected override void OnInitialized()
    {
        PdfSource = Convert.FromBase64String(PdfBase64);

        base.OnInitialized();
    }

        private const string PdfBase64 = "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";
    private FakeContext _fakeContext = new FakeContext() { Name = "Test" };
    public class FakeContext
    {
        public string Name { get; set; }
    }
}
    

<FilterMenuTemplate>
    <TelerikMultiSelect Value="@(AlreadySelectedFilterValues(context.FilterDescriptor))"
                        OnRead="@OnReadWrapper"
                        ValueMapper="@ValueMapperWrapper"
                        TItem="@FilterItemDto" 
                        TValue="@TFilterValue"
                        ValueField="@nameof(FilterItemDto.Id)"
                        TextField="@nameof(FilterItemDto.Name)"
                        AutoClose="true"
                        Filterable="true"
                        ClearButton="true"
                        DebounceDelay="500"
                        OnChange="@((object newValue) => OnMenuFilterChange(newValue, context))"/>
</FilterMenuTemplate>