public TelerikGrid<ExpandoObject> TelerikGrid { get; set; }

private bool IsPageable = false;

private int Page { get; set; }

public void ChangeHandler(bool value)
{
    //Sync the paging with scrolling

    if (value)
    {
        IsPageable = value;
        var state = TelerikGrid.GetState();
        state.Skip = 0;
        state.Page = 3;

        _ = TelerikGrid.SetState(state);
    }

    IsPageable = value;

    StateHasChanged();
}

@using Telerik.DataSource

<h2>No Aggregates</h2>

<p><code>OnStateInitCounter1:</code> @OnStateInitCounter1</p>
<TelerikGrid Data="@GridData"
             TItem="@SampleModel"
             Groupable="true"
             OnStateInit="@OnGridStateInit1">
    <GridAggregates>

    </GridAggregates>
    <GridColumns>
        <GridColumn Field="@nameof(SampleModel.Name)" />
        <GridColumn Field="@nameof(SampleModel.GroupName)" />
    </GridColumns>
</TelerikGrid>

<h2>With Aggregates</h2>

<p><code>OnStateInitCounter2:</code> @OnStateInitCounter2</p>
<TelerikGrid Data="@GridData"
             TItem="@SampleModel"
             Groupable="true"
             OnStateInit="@OnGridStateInit2">
    <GridAggregates>
        <GridAggregate Field="@nameof(SampleModel.Name)" Aggregate="@GridAggregateType.Count" />
    </GridAggregates>
    <GridColumns>
        <GridColumn Field="@nameof(SampleModel.Name)" />
        <GridColumn Field="@nameof(SampleModel.GroupName)" />
    </GridColumns>
</TelerikGrid>

<h2>With Aggregates and Workaround</h2>

<p><code>OnStateInitCounter3:</code> @OnStateInitCounter3</p>
<TelerikGrid Data="@GridData"
             TItem="@SampleModel"
             Groupable="true"
             OnStateInit="@OnGridStateInit3">
    <GridAggregates>
        <GridAggregate Field="@nameof(SampleModel.Name)" Aggregate="@GridAggregateType.Count" />
    </GridAggregates>
    <GridColumns>
        <GridColumn Field="@nameof(SampleModel.Name)" />
        <GridColumn Field="@nameof(SampleModel.GroupName)" />
    </GridColumns>
</TelerikGrid>

@code {
    private int OnStateInitCounter1 { get; set; }
    private int OnStateInitCounter2 { get; set; }
    private int OnStateInitCounter3 { get; set; }

    private void OnGridStateInit1(GridStateEventArgs<SampleModel> args)
    {
        ++OnStateInitCounter1;

        args.GridState.GroupDescriptors.Add(new GroupDescriptor
        {
            Member = nameof(SampleModel.GroupName)
        });
    }

    private void OnGridStateInit2(GridStateEventArgs<SampleModel> args)
    {
        ++OnStateInitCounter2;

        args.GridState.GroupDescriptors.Add(new GroupDescriptor
        {
            Member = nameof(SampleModel.GroupName)
        });
    }

    private void OnGridStateInit3(GridStateEventArgs<SampleModel> args)
    {
        ++OnStateInitCounter3;

        args.GridState.GroupDescriptors = new List<GroupDescriptor>();
        // OR
        args.GridState.GroupDescriptors.Clear();

        args.GridState.GroupDescriptors.Add(new GroupDescriptor
        {
            Member = nameof(SampleModel.GroupName)
        });
    }

    private List<SampleModel> GridData { get; set; } = new();

    protected override void OnInitialized()
    {
        for (int i = 1; i <= 4; i++)
        {
            GridData.Add(new SampleModel()
            {
                Id = i,
                Name = $"Name {i}",
                GroupName = $"Group {i % 2 + 1}"
            });
        }
    }

    public class SampleModel
    {
        public int Id { get; set; }
        public string Name { get; set; } = string.Empty;
        public string GroupName { get; set; } = string.Empty;
    }
}

@using Telerik.Blazor
@using Telerik.Blazor.Components.Grid

<TelerikGrid Data=@GridData
             SelectionMode="GridSelectionMode.Multiple"
             @bind-SelectedItems="SelectedItems"
             Pageable="true"
             Height="400px">
    <TelerikGridToolBar>
        <TelerikGridCommandButton Command="MyDelete" OnClick="DeleteSelectedAsync"
                                         Enabled=@(SelectedItems?.Count() > 0) Icon="delete">Delete</TelerikGridCommandButton>
        <TelerikGridCommandButton Enabled="false" OnClick="DeleteSelectedAsync">I must always be disabled</TelerikGridCommandButton>
</TelerikGridToolBar>
    <TelerikGridColumns>
        <TelerikGridCheckboxColumn />
        <TelerikGridColumn Field=@nameof(Employee.Name) />
        <TelerikGridColumn Field=@nameof(Employee.Team) Title="Team" />
    </TelerikGridColumns>
</TelerikGrid>

@result

@if (SelectedItems != null)
{
    <ul>
        @foreach (Employee employee in SelectedItems)
        {
            <li>
                @employee.Name
            </li>
        }
    </ul>
}

@code {
    void DeleteSelectedAsync()
    {
        result = $"On {DateTime.Now} there are {SelectedItems?.Count()} items selected";
    }
    string result;

    public List<Employee> GridData { get; set; }
    public IEnumerable<Employee> SelectedItems { get; set; }

    protected override void OnInitialized()
    {
        GridData = new List<Employee>();
        for (int i = 0; i < 15; i++)
        {
            GridData.Add(new Employee()
            {
                EmployeeId = i,
                Name = "Employee " + i.ToString(),
                Team = "Team " + i % 3
            });
        }

        // select Employee with 3 through 5
        SelectedItems = GridData.Skip(2).Take(3).ToList();
    }

    public class Employee
    {
        public int EmployeeId { get; set; }
        public string Name { get; set; }
        public string Team { get; set; }
    }
}

    .k-grid .k-grouping-header {
        padding: 0;
        border-bottom-width: 0;
        gap: 0;
    }

        .k-grid .k-grouping-header::before {
            margin: 0;
        }

    .k-grid .k-grouping-header .k-grouping-drop-container {
        margin: 0;
    }