CustomMessageBox.xaml

<Window x:Class="Google_Bookmarks_Manager_for_GPOs.CustomMessageBox"
              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"
        xmlns:local="clr-namespace:Google_Bookmarks_Manager_for_GPOs"
        xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
        TextElement.Foreground="{DynamicResource MaterialDesignBody}"
        Background="{DynamicResource MaterialDesignPaper}"
        TextElement.FontWeight="Medium"
        TextElement.FontSize="14"
        FontFamily="{materialDesign:MaterialDesignFont}"
        mc:Ignorable="d"
        Title="CustomMessageBox" Height="200" Width="400">

    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="*" />
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>
        <TextBlock Name="MessageTextBlock" Text="Message" Margin="20" TextWrapping="Wrap" />
        <StackPanel Grid.Row="1" Orientation="Horizontal" HorizontalAlignment="Center" Margin="0,20">
            <Button Name="OKButton" Content="OK" Width="100" Height="30" Margin="10" Click="OKButton_Click" />
            <Button Name="CancelButton" Content="Cancel" Width="100" Height="30" Margin="10" Click="CancelButton_Click" />
        </StackPanel>
    </Grid>
</Window>