MetroWindow.xaml

<mah:MetroWindow  x:Class="FluentRibbonTest.MetroWindow"
                      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                      xmlns:Fluent="urn:fluent-ribbon" 
                      xmlns:mah="http://metro.mahapps.com/winfx/xaml/controls"
                      xmlns:fluentribbontest="clr-namespace:FluentRibbonTest" 
                      xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
                        xmlns:iconPacks="http://metro.mahapps.com/winfx/xaml/iconpacks"
                      Title="My first RibbonWindow" 
GlowBrush="{DynamicResource MahApps.Brushes.Accent}"
                   ShowIconOnTitleBar="False"
                   ShowSystemMenuOnRightClick="False"
                   ShowTitleBar="True"
                   TitleCharacterCasing="Normal"
                   WindowStartupLocation="CenterScreen"
                   WindowState="Normal"
                   WindowTransitionsEnabled="False"
                      Width="800" 
                      Height="600">

    <mah:MetroWindow.Resources>
        <BooleanToVisibilityConverter x:Key="boolToVisibilityConverter" />

        <Style x:Key="{x:Type Fluent:BackstageTabControl}"
                   BasedOn="{StaticResource {x:Type Fluent:BackstageTabControl}}"
                   TargetType="{x:Type Fluent:BackstageTabControl}">
            <Setter Property="SelectedContentMargin" Value="0" />
        </Style>
    </mah:MetroWindow.Resources>

    <mah:MetroWindow.TitleTemplate>
        <DataTemplate>
            <Fluent:RibbonTitleBar x:Name="RibbonTitleBar"    
                                   DataContext="{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=DataContext}"
                                   Header="{Binding Path=Title, RelativeSource={RelativeSource AncestorType=Window}}"/>
        </DataTemplate>
    </mah:MetroWindow.TitleTemplate>

    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="*" />
        </Grid.RowDefinitions>

        <Fluent:Ribbon Grid.Row="0" x:Name="ribbon"
                       AutomaticStateManagement="True"
                       IsSimplified="False"
                       CanUseSimplified="True">

            <!--Backstage-->
            <Fluent:Ribbon.Menu>
                <Fluent:Backstage UseHighestAvailableAdornerLayer="False">
                    <Fluent:BackstageTabControl x:Name="backstageTabControl" SelectedContentMargin="0">
                        <Fluent:Button Header="Demo" />
                    </Fluent:BackstageTabControl>
                </Fluent:Backstage>
            </Fluent:Ribbon.Menu>

            <!--Contextual Tab Groups-->
            <Fluent:Ribbon.ContextualGroups>
                <Fluent:RibbonContextualTabGroup x:Name="toolsGroup"
                                                 Header="Binding" 
                                                 Background="{DynamicResource Fluent.Ribbon.Brushes.AccentBaseColorBrush}"
                                                 BorderBrush="{DynamicResource Fluent.Ribbon.Brushes.AccentBaseColorBrush}"
                                                 Foreground="{DynamicResource BlackBrush}"
                                                 TabItemMouseOverForeground="Red"
                                                 TabItemSelectedForeground="{DynamicResource Fluent.Ribbon.Brushes.RibbonTabItem.Foreground}"
                                                 TabItemSelectedMouseOverForeground="OrangeRed"
                                                 Visibility="{Binding IsTabGroupVisible, Converter={StaticResource boolToVisibilityConverter}}"/>

                <Fluent:RibbonContextualTabGroup x:Name="visibleGroup"
                                                 Header="No Binding" 
                                                 Visibility="Visible"
                                                 Background="Green" BorderBrush="Green"
                                                 Foreground="Black"/>

            </Fluent:Ribbon.ContextualGroups>


            <!--Tabs-->
            <Fluent:RibbonTabItem Header="Home">
                <Fluent:RibbonGroupBox Header="Group">
                    <Fluent:Button Header="Show/Hide Tab"
                                   LargeIcon="{StaticResource DocumentIcon}"
                                   Command="{Binding ShowHideTab}"/>
                </Fluent:RibbonGroupBox>
            </Fluent:RibbonTabItem>

            <!--Contextual Tabs-->
            <Fluent:RibbonTabItem Header="Contextual Group" 
                                  BorderBrush="{DynamicResource Fluent.Ribbon.Brushes.AccentBaseColorBrush}"
                                  ActiveTabBackground="Red"
                                  Group="{Binding ElementName=toolsGroup, Mode=OneWay}"
                                  Visibility="Visible">
                <Fluent:RibbonGroupBox Header="Box 1">
                    <Fluent:ComboBox Header="Check Me" />
                </Fluent:RibbonGroupBox>
                <Fluent:RibbonGroupBox Header="Box 2">
                    <Fluent:ComboBox Header="Check Me Too" />
                </Fluent:RibbonGroupBox>
            </Fluent:RibbonTabItem>

            <Fluent:RibbonTabItem Header="Contextual Group"
                                  Visibility="Visible"
                                  Group="{Binding ElementName=visibleGroup, Mode=OneWay}">
            </Fluent:RibbonTabItem>


        </Fluent:Ribbon>



        <TextBlock Text="Is visible!" Grid.Row="1"
                   Visibility="{Binding IsTabGroupVisible, Converter={StaticResource boolToVisibilityConverter}}"
                   />

    </Grid>
</mah:MetroWindow>