Here is the code highlight active menu item on Menu control throught XAML. 
- <Style TargetType="MenuItem">  
-     <Style.Triggers>  
-         <Trigger Property="IsFocused" Value="True" >  
-             <Setter Property="Background" Value="White" />  
-             <Setter Property="Foreground" Value="Black" />  
-         </Trigger>  
-     </Style.Triggers>  
- </Style>