MainWindow.xaml

<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:mvvm="http://schemas.devexpress.com/winfx/2008/xaml/mvvm"
        xmlns:dxp="http://schemas.devexpress.com/winfx/2008/xaml/printing"  
        xmlns:dxpp="clr-namespace:DevExpress.Xpf.Printing.Parameters;assembly=DevExpress.Xpf.Printing.v15.2"     
        xmlns:dxe="http://schemas.devexpress.com/winfx/2008/xaml/editors" 
        xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core" 
        xmlns:local="clr-namespace:CustomParameterEditorsWPF"
        xmlns:dxb="http://schemas.devexpress.com/winfx/2008/xaml/bars" xmlns:System="clr-namespace:System;assembly=mscorlib" x:Class="CustomParameterEditorsWPF.MainWindow"
        Title="MainWindow" Height="720" Width="1280">

    <Window.Resources>
        <local:CustomParameterTemplateSelector x:Key="parameterTemplateSelector">
            <local:CustomParameterTemplateSelector.Templates>
                <DataTemplate x:Key="multiValueTemplate">
                    <dxpp:ParameterLineLayout>
                        <dxe:ComboBoxEdit Grid.Column="1" MinWidth="70" ShowCustomItems="True"
                			IncrementalFiltering="False" AutoComplete="True" ImmediatePopup="True"
                			ItemsSource="{Binding LookUpValues}" DisplayMember="RealDescription" ValueMember="Value" MaxHeight="90" FocusPopupOnOpen="False">
                            <mvvm:Interaction.Behaviors>
                                <dxpp:MutliValueBindingProvider SourceType="{Binding Type}" />
                                <dxpp:ShowPopupBehavior />
                            </mvvm:Interaction.Behaviors>
                            <dxe:ComboBoxEdit.StyleSettings>
                                <dxe:CheckedTokenComboBoxStyleSettings AllowEditTokens="False" EnableTokenWrapping="True" ShowTokenButtons="True" NewTokenPosition="Far" />
                            </dxe:ComboBoxEdit.StyleSettings>
                        </dxe:ComboBoxEdit>
                    </dxpp:ParameterLineLayout>
                </DataTemplate>
            </local:CustomParameterTemplateSelector.Templates>
        </local:CustomParameterTemplateSelector>
        <Style TargetType="{x:Type dxpp:ParametersPanel}">
            <Setter Property="ParameterTemplateSelector" Value="{StaticResource parameterTemplateSelector}" />
        </Style>
    </Window.Resources>
    <dxp:DocumentPreviewControl x:Name="preview" />
</Window>