PopUp.XAML

<UserControl x:Class="Equity_Order_Book.AppSelectionControl"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
             xmlns:local="clr-namespace:Equity_Order_Book"
             VerticalAlignment="Center"
             HorizontalAlignment="Center"
             Background="Transparent" >

    <UserControl.Resources>
        <local:GroupingTitleInstanceConverter x:Key="GroupingTitleInstanceConverter"/>
        <local:DisplayTitleInstanceConverter x:Key="DisplayTitleInstanceConverter"/>
        <local:StringToImageSourceConverter x:Key="StringToImageSourceConverter"/>

    </UserControl.Resources>


    <Border Background="Gray" CornerRadius="20" ClipToBounds="True" Padding="7">
        <StackPanel Background="Gray" >
            <TextBlock x:Name ="IntentResolverTextBox"
                       FontSize="20"
                       FontFamily="Lucida Sans Unicode"
                       VerticalAlignment="Top"
                       Foreground="White" 
                       HorizontalAlignment="Center" />

            <ListBox x:Name="appListBox" 
                     SelectionMode="Single"
                     Opacity="1"
                     HorizontalAlignment="Stretch"
                     Width="442"
                     Height="417">

                <!-- GroupStyle to display group headers -->
                <ListBox.GroupStyle>
                    <GroupStyle>
                        <GroupStyle.HeaderTemplate>
                            <DataTemplate>
                                <Border Background="LightGray" CornerRadius="5" Padding="5" Margin="2">
                                    <TextBlock Text="{Binding Name}" FontWeight="Bold" />
                                </Border>
                            </DataTemplate>
                        </GroupStyle.HeaderTemplate>
                    </GroupStyle>
                </ListBox.GroupStyle>


                <ListBox.ItemContainerStyle>
                    <Style TargetType="ListBoxItem">
                        <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
                        <Setter Property="Template">
                            <Setter.Value>
                                <ControlTemplate TargetType="ListBoxItem">
                                    <Border Name="Border" BorderBrush="Gray" BorderThickness="0,0,0,1">
                                        <ContentPresenter />
                                    </Border>
                                </ControlTemplate>
                            </Setter.Value>
                        </Setter>
                    </Style> 
                </ListBox.ItemContainerStyle>
                
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <Grid>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="Auto"/>
                                <!-- First Image -->
                                <ColumnDefinition Width="*"/>
                                <!-- TextBlock and Spacer -->
                                <ColumnDefinition Width="Auto"/>
                                <!-- Second Image -->
                            </Grid.ColumnDefinitions>

                            <Image Grid.Column="0"
                                   Source="{Binding FirstIconSrc}" 
                                   Width="30" 
                                   Height="30" 
                                   Margin="3"/>

                            <TextBlock Grid.Column="1" 
                                       Margin="3" 
                                       Padding="3" 
                                       FontFamily="Lucida Sans Unicode" 
                                       FontSize="15"
                                       Text="{Binding Path=., Converter={StaticResource DisplayTitleInstanceConverter}}"
                                       x:Name="appNameTextBlock"/>

                            <Image Grid.Column="2" 
                                   Width="30" 
                                   Height="30" 
                                   Loaded="OnImageLoaded"
                                   Margin="10"
                                   HorizontalAlignment="Right">
                            </Image>
                        </Grid>

                    </DataTemplate>
                </ListBox.ItemTemplate>
            </ListBox>
        </StackPanel>
    </Border>
</UserControl>