BPA.SingleDevice/BPA.UIControl/MessageWindow.xaml

<Window x:Class="BPA.UIControl.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:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        VerticalAlignment="Top"
        AllowsTransparency="True"
        Background="Transparent"
        ShowInTaskbar="False"
        Topmost="True"
        WindowStartupLocation="CenterOwner"
        WindowState="Maximized"
        WindowStyle="None"
        mc:Ignorable="d">
    <StackPanel x:Name="messageStackPanel" Margin="10" />
</Window>