msfs-popout-panel-manager/MainApp/MessageWindow.xaml

<Window
    x:Class="MSFSPopoutPanelManager.MainApp.MessageWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:system="clr-namespace:System;assembly=mscorlib"
    xmlns:viewmodel="clr-namespace:MSFSPopoutPanelManager.MainApp.ViewModel"
    Title="MSFS Pop Out Panel Manager"
    Width="Auto"
    Height="Auto"
    AllowsTransparency="True"
    ResizeMode="NoResize"
    ShowInTaskbar="False"
    SizeToContent="WidthAndHeight"
    Topmost="True"
    WindowStyle="None"
    mc:Ignorable="d">
    <Window.Resources>
        <system:Double x:Key="IconSize">22</system:Double>
        <system:Double x:Key="ButtonSize">28</system:Double>
        <Style
            x:Key="Label"
            BasedOn="{StaticResource MaterialDesignBody1TextBlock}"
            TargetType="TextBlock">
            <Setter Property="Foreground" Value="White" />
        </Style>
    </Window.Resources>
    <materialDesign:ColorZone
        Width="Auto"
        Height="Auto"
        Mode="Dark">
        <DockPanel
            Width="400"
            Height="225"
            d:DataContext="{d:DesignInstance viewmodel:MessageWindowViewModel}">
            <WrapPanel
                Height="30"
                Background="SlateGray"
                DockPanel.Dock="Top">
                <TextBlock
                    Padding="10,5,10,5"
                    HorizontalAlignment="Stretch"
                    Style="{StaticResource MaterialDesignBody1TextBlock}">
                    MSFS POP OUT PANEL MANAGER
                </TextBlock>
            </WrapPanel>
            <WrapPanel Margin="20,5,20,10">
                <ScrollViewer
                    x:Name="ScrollViewerMessage"
                    Height="Auto"
                    DockPanel.Dock="Bottom"
                    HorizontalScrollBarVisibility="Hidden"
                    VerticalScrollBarVisibility="Hidden">
                    <TextBlock
                        x:Name="TextBlockMessage"
                        LineHeight="18"
                        LineStackingStrategy="BlockLineHeight" />
                </ScrollViewer>
            </WrapPanel>
        </DockPanel>
    </materialDesign:ColorZone>
</Window>