i have xamgrid with using 12.2 version dll below is the source code.  in any row if i try to enter empty value, its not accepting instead it will retain the old value. i found the below url. it doen't telling what i need to install. i do have product key with me. could you please help me out.

http://stackoverflow.com/questions/15755772/xamgrid-doesnt-allow-to-select-empty-text

<ig:XamGrid x:Name="XamMetaGrid"

            HorizontalAlignment="Left"      

              Margin="5,52,0,42" PreviewTextInput="XamMetaGrid_PreviewTextInput" PreviewKeyDown="XamMetaGrid_OnPreviewKeyDown"

              ItemsSource="{Binding FillGrid, Mode=TwoWay}" IsEnabled="True" Width="601">          

            <ig:XamGrid.Columns>

                <ig:UnboundColumn Key="EditColumn" HeaderText=" " Visibility ="{Binding ColumnVisibilityCustom.ColumnVisibility, Source={StaticResource proxy}}">

                    <ig:UnboundColumn.ItemTemplate>

                        <DataTemplate>

                            <StackPanel Orientation="Horizontal" >

                                <Button Content="Edit" Width="40" Click="EditButton_Click">

                                    <ig:Commanding.Command>

                                        <ig:XamGridRowCommandSource EventName="Click" AllowEventHandling="True" CommandType="Edit" >

                                        </ig:XamGridRowCommandSource>

                                    </ig:Commanding.Command>

                                </Button>

                            </StackPanel>                           

                        </DataTemplate>

                    </ig:UnboundColumn.ItemTemplate>

                </ig:UnboundColumn>

            </ig:XamGrid.Columns>

            <ig:XamGrid.SelectionSettings>

                <ig:SelectionSettings ColumnSelection="Single" RowSelection="Single" CellClickAction="SelectRow"  >

                </ig:SelectionSettings>

            </ig:XamGrid.SelectionSettings>

            <ig:XamGrid.EditingSettings>

                <ig:EditingSettings />

            </ig:XamGrid.EditingSettings>

            <ig:XamGrid.PagerSettings>

                <ig:PagerSettings AllowPaging="Bottom"

                            PageSize="100" />

            </ig:XamGrid.PagerSettings>

            <ig:XamGrid.ColumnTypeMappings>

                <ig:ColumnTypeMapping ColumnType="ig:TextColumn" DataType="system:DateTime" />

            </ig:XamGrid.ColumnTypeMappings>

        </ig:XamGrid>