The menu actually is a StackPanel with HyperlinkButton controls placed in it. The HyperlinkButton control is using a custom Style. Check the code snippet bellow:
<LinearGradientBrush x:Key="ProductsButtonBackground_Over"
EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#FF3D414C" Offset="0" />
<GradientStop Color="#FF1D1F23" Offset="1" />
<GradientStop Color="#FF30333C" Offset="0.05" />
</LinearGradientBrush>
<Style x:Key="ProductButton" TargetType="HyperlinkButton">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="HyperlinkButton">
<Grid Margin="6,0,6,24"
VerticalAlignment="Center">
<VisualStateManager.VisualStateGroups>
<VisualStateGroup
x:Name="CommonStates">
<VisualState x:Name="Normal" />
<VisualState x:Name="MouseOver">
<Storyboard>
<DoubleAnimationUsingKeyFrames
Storyboard.TargetName="BackgroundAnimation"
Storyboard.TargetProperty="Opacity">
<SplineDoubleKeyFrame
KeyTime="0"
Value="1" />
</DoubleAnimationUsingKeyFrames>
<DoubleAnimationUsingKeyFrames
Storyboard.TargetName="contentPresenter"
Storyboard.TargetProperty="Opacity">
<SplineDoubleKeyFrame
KeyTime="0"
Value="1" />
</DoubleAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="Pressed">
<Storyboard>
<DoubleAnimationUsingKeyFrames
Storyboard.TargetName="BackgroundAnimation"
Storyboard.TargetProperty="Opacity">
<SplineDoubleKeyFrame
KeyTime="0"
Value="1" />
</DoubleAnimationUsingKeyFrames>
<DoubleAnimationUsingKeyFrames
Storyboard.TargetName="contentPresenter"
Storyboard.TargetProperty="Opacity">
<SplineDoubleKeyFrame
KeyTime="0"
Value="1" />
</DoubleAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="Disabled">
<Storyboard>
<DoubleAnimationUsingKeyFrames
Storyboard.TargetName="BackgroundAnimation"
Storyboard.TargetProperty="Opacity">
<SplineDoubleKeyFrame
KeyTime="0"
Value="0.30" />
</DoubleAnimationUsingKeyFrames>
<DoubleAnimationUsingKeyFrames
Storyboard.TargetName="contentPresenter"
Storyboard.TargetProperty="Opacity">
<SplineDoubleKeyFrame
KeyTime="0"
Value="0.30" />
</DoubleAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup
x:Name="FocusStates">
<VisualState x:Name="Focused" />
<VisualState x:Name="Unfocused" />
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Border x:Name="Background" Height="44">
<Grid>
<Border
x:Name="BackgroundAnimation"
Opacity="0"
Background="{StaticResource ProductsButtonBackground_Over}" />
<Rectangle
x:Name="BackgroundGradient"
Fill="#00FFFFFF" />
</Grid>
</Border>
<ContentPresenter
HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
Margin="6,10"
x:Name="contentPresenter"
VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
Content="{TemplateBinding Content}"
ContentTemplate="{TemplateBinding ContentTemplate}"
Opacity=".65" />
<Rectangle
x:Name="DisabledVisualElement"
IsHitTestVisible="false"
Opacity="0" Fill="{x:Null}" />
<Rectangle Margin="1"
x:Name="FocusVisualElement"
IsHitTestVisible="false"
Opacity="0" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>