WPF

<Style x:Key="ToggleButtonStyle" TargetType="{x:Type ToggleButton}">
    <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
    <Setter Property="HorizontalContentAlignment" Value="Center"/>
    <Setter Property="VerticalContentAlignment" Value="Center"/>
    <Setter Property="Padding" Value="1"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type ToggleButton}">
                <Grid>
                    <Border Background="Black" BorderThickness="1" BorderBrush="#FF4E4F50" CornerRadius="3"/>
                    <Border Background="Black" Margin="1" CornerRadius="3"/>
                    <Border Margin="2" CornerRadius="3">
                        <Border.Background>
                            <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                                <GradientStop Color="#0099B9D1" Offset="0"/>
                                <GradientStop Color="#FF99B9D1" Offset="1"/>
                                <GradientStop Color="#B299B9D1" Offset="0.054"/>
                            </LinearGradientBrush>
                        </Border.Background>
                    </Border>
                    <Border Margin="2" CornerRadius="3" Opacity="0.3">
                        <Border.Background>
                            <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                                <LinearGradientBrush.RelativeTransform>
                                    <TransformGroup>
                                        <ScaleTransform CenterY="0.5" CenterX="0.5"/>
                                        <SkewTransform CenterY="0.5" CenterX="0.5"/>
                                        <RotateTransform Angle="90" CenterY="0.5" CenterX="0.5"/>
                                        <TranslateTransform/>
                                    </TransformGroup>
                                </LinearGradientBrush.RelativeTransform>
                                <GradientStop Color="Black" Offset="0"/>
                                <GradientStop Color="Black" Offset="1"/>
                                <GradientStop Color="#00090909" Offset="0.022"/>
                                <GradientStop Color="#00000000" Offset="0.99"/>
                                <GradientStop Color="#45060606" Offset="0.001"/>
                            </LinearGradientBrush>
                        </Border.Background></Border>

                    <ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                    </Grid>


                <ControlTemplate.Triggers>
                    <Trigger Property="IsKeyboardFocused" Value="true">

                    </Trigger>
                    <Trigger Property="IsChecked" Value="true">

                    </Trigger>
                    <Trigger Property="IsEnabled" Value="false">
                        <Setter Property="Foreground" Value="#ADADAD"/>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

<Menu DockPanel.Dock="Top">
        <ComboBox  IsEditable="False" Width="{Binding Path=ActualWidth, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Menu}}"></ComboBox>
</Menu>

comboBoxProcessList.Width = (Double)((Menu)sender).ActualWidth - 15;

<ribbon:RibbonWindow
    x:Name="window"
    x:Class="MHManager.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:MHManager"
    xmlns:classes="clr-namespace:MHManager.Classes"
    xmlns:controls="clr-namespace:MHManager.Controls"
    xmlns:shared="http://schemas.actiprosoftware.com/winfx/xaml/shared"
    xmlns:ribbon="http://schemas.actiprosoftware.com/winfx/xaml/ribbon"
    xmlns:themes="http://schemas.actiprosoftware.com/winfx/xaml/themes"
	xmlns:editors="http://schemas.actiprosoftware.com/winfx/xaml/editors"    
	xmlns:ribboneditors="http://schemas.actiprosoftware.com/winfx/xaml/ribboneditors"
    xmlns:s="http://www.stemasoft.com/xaml"
    xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
    xmlns:ComponentModel="clr-namespace:System.ComponentModel;assembly=WindowsBase"
    xmlns:System="clr-namespace:System;assembly=mscorlib"
    ResizeMode="CanResizeWithGrip" 
    ApplicationName="Manufactured Housing Manager"	    
    Icon="Icons/MHManagericon.ico"
    Background="{Binding Background, ElementName=navigationPane}"
    Height="632"
    Width="930" 
    Loaded="window_Loaded" Closed="applicationExitCommand_Execute">