I've created a XamDataGrid using multiple field layouts to display parent/child relationships. The grid is using the Metro theme. However, the header for the column that displays the expand/collapse control appears to be missing part of the grid outline, on the left hand side. See attached screenshot. This is confusing for users and only seems to occur when the grid is used with multiple field layouts.

The XAML is as follows:

<igWPF:XamDataGrid x:Name="XamDataGrid" Margin="30,30,10,10" Background="Transparent" GroupByAreaLocation="None" DataSource="{Binding}">

                        <igWPF:XamDataGrid.Resources>

                            <Style x:Key="CustomFieldCell" TargetType="{x:Type igWPF:CellValuePresenter}">

                                <Setter Property="Template">

                                    <Setter.Value>

                                        <ControlTemplate TargetType="{x:Type igWPF:CellValuePresenter}">

                                            <Path Data="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Value, Converter={StaticResource StatusTypePathConverter}}" Stretch="Uniform" Fill="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Value, Converter={StaticResource StateColorConverter}}" Width="30" Height="30" Margin="0,0,0,0" RenderTransformOrigin="0.5,0.5" HorizontalAlignment="Center">

                                            </Path>

                                        </ControlTemplate>

                                    </Setter.Value>

                                </Setter>

                            </Style>

                        </igWPF:XamDataGrid.Resources>

                        <igWPF:XamDataGrid.FieldSettings>

                            <igWPF:FieldSettings AllowEdit="True" CellClickAction="SelectRecord" LabelTextAlignment="Center"/>

                        </igWPF:XamDataGrid.FieldSettings>

                        <igWPF:XamDataGrid.FieldLayouts>

                            <igWPF:FieldLayout Key="ClassA">

                                <igWPF:FieldLayout.Settings>

                                    <igWPF:FieldLayoutSettings AutoGenerateFields="False" RecordSelectorLocation="None" LabelLocation="Default" SelectionTypeRecord="Single" ExpansionIndicatorDisplayMode="CheckOnDisplay"/>

                                </igWPF:FieldLayout.Settings>

                                <igWPF:Field Name="State" Label="" Width="Auto">

                                    <igWPF:Field.Settings>

                                        <igWPF:FieldSettings CellValuePresenterStyle="{StaticResource CustomFieldCell}"></igWPF:FieldSettings>

                                    </igWPF:Field.Settings>

                                </igWPF:Field>

                                <igWPF:UnboundField BindingPath="Title" Label="" Width="*"/>                               

                                <igWPF:Field Name="ClassBs" Label="" Width="*"/>

                            </igWPF:FieldLayout>

                            <igWPF:FieldLayout Key="ClassB">

                                <igWPF:FieldLayout.Settings>

                                    <igWPF:FieldLayoutSettings AutoGenerateFields="False" RecordSelectorLocation="None" LabelLocation="Hidden" SelectionTypeRecord="Single" ExpansionIndicatorDisplayMode="CheckOnDisplay"/>

                                </igWPF:FieldLayout.Settings>                               

                                <igWPF:Field Name="ID" Visibility="Collapsed"></igWPF:Field>

                                <igWPF:Field Name="State" Label="" Width="Auto">

                                    <igWPF:Field.Settings>

                                        <igWPF:FieldSettings CellValuePresenterStyle="{StaticResource CustomFieldCell}"></igWPF:FieldSettings>

                                    </igWPF:Field.Settings>

                                </igWPF:Field>

                                <igWPF:UnboundField BindingPath="Title" Label="Vulnerabilities" Width="*" ColumnSpan="4"/>                               

                            </igWPF:FieldLayout>                            

                        </igWPF:XamDataGrid.FieldLayouts>

                    </igWPF:XamDataGrid>