Avalonia/samples/Previewer/MainWindow.xaml

<Window xmlns="https://github.com/avaloniaui" Width="600" Height="500"
        Title="Previewer">
    <Grid RowDefinitions="0.5*,200">
        <ScrollViewer Name="Remote"/>
        
        <ScrollViewer Name="ErrorsContainer" Background="#ffe0e0">
            <TextBlock Name="Errors"/>
        </ScrollViewer>
        <TextBox Grid.Row="1" AcceptsReturn="True" Name="Xaml"/>
    </Grid>
    
</Window>