WPF

<Grid x:Name="layoutRoot">

<pre>
<Grid.RowDefinitions>
    <RowDefinition Height="Auto"/>
</Grid.RowDefinitions>

<Button Grid.Row="0" 
        Click="Button_Click">

    <StackPanel Orientation="Horizontal">
        <Image Source="sort_16.png"
                VerticalAlignment="Center"
                Height="16"
                Width="16"/>
        <Image Source="downarrow.png"
                VerticalAlignment="Center"
                Height="3"
                Width="5"/>

    </StackPanel>

    <Button.ContextMenu>
        <ContextMenu/>
    </Button.ContextMenu>

    <Button.Resources>

        <ContextMenu x:Key="menu" ItemsSource="{Binding MenuItems}">

            <ContextMenu.ItemTemplate> 
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">

                        <TextBlock  Text="{Binding Text}"/>
                        <MenuItem  Command="{Binding MenuItemSelectedCommand, Mode=TwoWay}"
                                    CommandParameter="{Binding}"/>

                    </StackPanel>
                </DataTemplate>
            </ContextMenu.ItemTemplate>

        </ContextMenu>

    </Button.Resources>

</Button>

public partial class DFTDropDownButton : UserControl
{
    #region Commands
    private ICommand _MenuItemSelectedCommand;
    public ICommand MenuItemSelectedCommand
    {
        get
        {
            if (_MenuItemSelectedCommand == null)
                _MenuItemSelectedCommand = new RelayCommand<DropDownButtonMenuItem>(p => menuItemSelectedExecuted(p), p => menuItemSelectedCanExecute());
            return _MenuItemSelectedCommand;
        }
    }
    #endregion

<pre>
#region MenuItems DP
public List<DropDownButtonMenuItem> MenuItems
{
    get { return (List<DropDownButtonMenuItem>)GetValue(MenuItemsProperty); }
    set { SetValue(MenuItemsProperty, value); }
}

<UserControl x:Class="WPFUserControl.UserControl1"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             mc:Ignorable="d" 
             xmlns:vis="clr-namespace:WPFUserControl"
             d:DesignHeight="300" d:DesignWidth="300">
    <UserControl.Resources>
        <vis:BoolToVisibilityConverter x:Key="BoolToVis" ></vis:BoolToVisibilityConverter>
    </UserControl.Resources>
    <Grid>
        <Button Content="Button1" HorizontalAlignment="Left" VerticalAlignment="Top" Width="75"/>
        <Button Content="Button2" HorizontalAlignment="Left" VerticalAlignment="Top" Width="75" Margin="106,0,0,0"/>
        <Button Content="ShowHide" Visibility="{Binding IsShowHideVisible, Converter={StaticResource BoolToVis}, ConverterParameter=False}" HorizontalAlignment="Left" VerticalAlignment="Top" Width="75" Margin="215,0,0,0"/>

    </Grid>
</UserControl>

public partial class UserControl1 : UserControl, INotifyPropertyChanged
    {
        private bool isShowHideVisible;
        public bool IsShowHideVisible
        {
            get { return isShowHideVisible; }
            set
            {
                if(isShowHideVisible!=value)
                {
                    isShowHideVisible = value;
                    OnPropertyChanged("IsShowHideVisible");
                }
            }
        }
        public UserControl1()
        {
            InitializeComponent();
           // IsShowHideVisible = false;
        }

        private void OnPropertyChange(string pPropertyName)
        {
            if(PropertyChanged!=null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(pPropertyName));
            }

        }

        public event PropertyChangedEventHandler PropertyChanged;
    }

<Expander Grid.Row="1"
            Grid.Column="2"
            BorderThickness="1" 
            BorderBrush="SteelBlue" 
            Background="White"
            ExpandDirection="Left"
            IsExpanded="False"
            HorizontalAlignment="Right"
            MaxWidth="150"
            Margin="0,0,5,5">

<pre>
<Expander.Effect>
    <DropShadowEffect/>
</Expander.Effect>

<Expander.Header>
    <TextBlock Text="My Stuff">
        <TextBlock.LayoutTransform>
            <RotateTransform Angle="90"/>
        </TextBlock.LayoutTransform>
    </TextBlock>
</Expander.Header>

<Grid>

    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="*"/>
    </Grid.RowDefinitions>

    <bc:DFTGrid>

        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*"/>
            <ColumnDefinition Width="Auto"/>
        </Grid.ColumnDefinitions>

        <bc:DFTComboBox Grid.Column="0" 
                        Style="{StaticResource ComboBoxStyle}"
                        Margin="2"/>

    </bc:DFTGrid>

    <bc:DFTListBox Grid.Row="1"
                    MinWidth="250"
                    ItemsSource="{Binding Sensors, Mode=TwoWay}"
                    ScrollViewer.VerticalScrollBarVisibility="Auto">

    </bc:DFTListBox>
</Grid>