This is happening because of the default style/template of a ContextMenu. You need to change the template of the MenuItem
s in your Menu
to achieve the results you desire. You can do this by defining a Style with Key="{x:Type MenuItem}"
in the Menu.Resources
:
<Menu>
<Menu.Resources>
<Style x:Key="{x:Type MenuItem}" TargetType="{x:Type MenuItem}">
<Style Property="Template">
<Style.Value>
<ControlTemplate TargetType="{x:Type MenuItem}">
<!-- your template parts here using -->
</ControlTemplate>
</Style.Value>
</Style>
</Style>
</Menu.Resources>
</Menu>