I'm using a XamDataGrid and customizing my field layout so I can insert a checkbox into the header label. Then I'm sorting the field so I have multiple sections, and I end up wth the checkbox only displaying in one of the two grid headers. Not sure how I can get it to display in both?

                    <dataPresenter:XamDataGrid x:Name="FwModuleGrid" b:XamDataGridBehavior.ExpandGroups="True" DataSource="{Binding UpgradableModules}" IsNestedDataDisplayEnabled="False" Style="{DynamicResource DefaultXamDataGridStyle}">
                        <dataPresenter:XamDataGrid.FieldLayoutSettings>
                            <b:XamDataGridDefaultFieldLayoutSettings AllowClipboardOperations="Copy"
                                                                     AutoFitMode="ExtendLastField"
                                                                     AutoGenerateFields="False"
                                                                     CopyFieldLabelsToClipboard="True"
                                                                     DataRecordCellAreaStyle="{DynamicResource DefaultXamDataGridDataRecordCellArea}"
                                                                     RecordSelectorLocation="None"
                                                                     SelectionTypeRecord="Extended"
                                                                     GroupByRecordChildIndent="0"/>
                        </dataPresenter:XamDataGrid.FieldLayoutSettings>
                        <dataPresenter:XamDataGrid.FieldSettings>
                            <dataPresenter:FieldSettings AllowRecordFiltering="False"
                                                         AutoSizeOptions="All"
                                                         AutoSizeScope="AllRecords"
                                                         CellClickAction="EnterEditModeIfAllowed"
                                                         EditModeBehaviorOnDataUpdate="UpdateEditValue" />
                        </dataPresenter:XamDataGrid.FieldSettings>
                        <dataPresenter:XamDataGrid.FieldLayouts>
                            <dataPresenter:FieldLayout>
                                <dataPresenter:FieldLayout.SortedFields>
                                    <dataPresenter:FieldSortDescription Direction="Descending" FieldName="System" IsGroupBy="True" />
                                    <dataPresenter:FieldSortDescription Direction="Descending" FieldName="Base" IsGroupBy="True" />
                                    <dataPresenter:FieldSortDescription Direction="Ascending" FieldName="Slot" />
                                </dataPresenter:FieldLayout.SortedFields>
                                <dataPresenter:Field Name="IsSelected" Width="Auto" HorizontalContentAlignment="Left" IsEnabled="{Binding CanSelect}" ToolTip="{x:Static strings:AutoStrings.Selected}">
				    <! -- This works for a single field, but when I add multiple fields with the field sorting it only shows up in the last field label -->   
                                    <dataPresenter:Field.Label>
                                        <ContentControl Content="{Binding DataContext, RelativeSource={RelativeSource AncestorType={x:Type dataPresenter:XamDataGrid}}}">
                                            <ContentControl.ContentTemplate>
                                                <DataTemplate >
                                                    <CheckBox IsChecked="{Binding IsAllChecked}"
                                                              IsThreeState="True"
                                                              IsEnabled="{Binding Path=DataItem.CanSelect}"
                                                              ToolTip="{x:Static strings:AutoStrings.SelectAll}" />
                                                </DataTemplate>
                                            </ContentControl.ContentTemplate>
                                        </ContentControl>
                                    </dataPresenter:Field.Label>
                                    <dataPresenter:Field.Settings>
                                        <dataPresenter:FieldSettings EditAsType="{x:Type sys:Boolean}" LabelClickAction="Nothing">
                                            <dataPresenter:FieldSettings.CellValuePresenterStyle>
                                                <Style TargetType="{x:Type dataPresenter:CellValuePresenter}">
                                                    <Setter Property="Value" Value="{Binding Path=DataItem.IsSelected}" />
                                                    <Setter Property="ToolTip" Value="{x:Static strings:AutoStrings.Selected}" />
                                                    <Setter Property="Tag" Value="{Binding Path=DataItem}" />
                                                    <Setter Property="IsEnabled" Value="{Binding Path=DataItem.CanSelect}" />
                                                    <Setter Property="Margin" Value="6" />
                                                    <Setter Property="Width" Value="Auto" />
                                                    <Setter Property="Template">
                                                        <Setter.Value>
                                                            <ControlTemplate TargetType="{x:Type dataPresenter:CellValuePresenter}">
                                                                <CheckBox IsChecked="{Binding Path=Tag.IsSelected, RelativeSource={RelativeSource AncestorType={x:Type dataPresenter:CellValuePresenter}}}" />
                                                            </ControlTemplate>
                                                        </Setter.Value>
                                                    </Setter>
                                                </Style>
                                            </dataPresenter:FieldSettings.CellValuePresenterStyle>
                                        </dataPresenter:FieldSettings>
                                    </dataPresenter:Field.Settings>
                                </dataPresenter:Field>
				<! -- other fields here -->                              
                            </dataPresenter:FieldLayout>
                        </dataPresenter:XamDataGrid.FieldLayouts>
                    </dataPresenter:XamDataGrid>

You can see the bottom column header label displays the checkbox, but the top one is missing. Normally I would think this is an issue with sharing the template between columns, so I tried turning the content presenter into a resource and then tagged it as x:Shared="false", but that didn't seem to do anything.

Any help would be appreciated!