DataGrid for Blazor - NullReferenceException occurs if the grid is empty and DxDataGridComboBoxColumn is used with a hidden filter row

To reproduce the issue, click the "New" button. In the Web Console (F12), you will see the error message.

Code:

Razor
<DxDataGrid Data="@Forecasts" PageSize="5"  ShowPager="false"
            ShowFilterRow="false"

            RowUpdating=@((updatingDataItem, newValues) => OnRowUpdating(updatingDataItem, newValues))
            RowInserting=@((newValues) => OnRowInserting(newValues))>

    <DxDataGridCommandColumn Width="150px" />
    <DxDataGridColumn Field="@nameof(WeatherForecast.Date)"></DxDataGridColumn>
    <DxDataGridColumn Field="@nameof(WeatherForecast.TemperatureC)"></DxDataGridColumn>
    <DxDataGridColumn Field="@nameof(WeatherForecast.TemperatureF)"></DxDataGridColumn>
    <DxDataGridComboBoxColumn Data="@WeatherForecastService.Summaries" TextFieldName="@nameof(WeatherForecast.Summary)" ValueFieldName="@nameof(WeatherForecast.Summary)" Field="@nameof(WeatherForecast.Summary)"></DxDataGridComboBoxColumn>
</DxDataGrid>

@code {
    List<WeatherForecast> Forecasts;

    protected override async Task OnInitializedAsync()
    {
        Forecasts = new List<WeatherForecast>();

    }

    async void OnRowUpdating(WeatherForecast item, Dictionary<string, object> newValue)
    {

    }

    async void OnRowInserting(Dictionary<string, object> newValue)
    {

    }
}