✅ MenuItem outline WPF

<Style TargetType="MenuItem">
    <Setter Property="Background" Value="#2C2C2C"/>
    <Setter Property="Foreground" Value="White"/>
    <Setter Property="BorderThickness" Value="0"/>
    <Style.Triggers>
        <Trigger Property="IsMouseOver" Value="True">
            <Setter Property="Background" Value="#383838"/>
        </Trigger>
    </Style.Triggers>
</Style>

<DockPanel>
    <Menu DockPanel.Dock="Top"
          Background="#2C2C2C"
          Foreground="White"
          BorderBrush="#404040"
          BorderThickness="0,0,0,1" Height="25">
        <MenuItem Header="File" Height="25">
            <MenuItem Header="New Tab" Click="NewTab_Click"/>
        </MenuItem>
    </Menu>

    <TabControl x:Name="EditorTabs" Background="#272727" BorderThickness="0"/>
</DockPanel>