MainPage.xaml

<Page
    x:Class="XmlSyntaxVisualizerUwp.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:XmlSyntaxVisualizerUwp"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:monaco="using:Monaco"
    xmlns:muxc="using:Microsoft.UI.Xaml.Controls"
    mc:Ignorable="d"
    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">

    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="2*"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition/>
            <ColumnDefinition/>
        </Grid.ColumnDefinitions>

        <monaco:CodeEditor x:Name="XmlEditor"
                           Loading="XmlEditor_Loading"/>

        <ScrollViewer Grid.Row="1">
            <TextBlock x:Name="CleanedXml"/>
        </ScrollViewer>

        <muxc:TreeView x:Name="XmlSyntaxTree" Grid.Column="1"
                       Grid.RowSpan="2"
                       ItemsSource="{x:Bind RootNodes, Mode=OneWay}"
                       ItemInvoked="XmlSyntaxTree_ItemInvoked">
            <muxc:TreeView.ItemTemplate>
                <DataTemplate x:DataType="local:XmlSyntaxData">
                    <muxc:TreeViewItem ItemsSource="{x:Bind Children}"
                                       IsExpanded="True"
                                       PointerMoved="TreeViewItem_PointerMoved">
                        <Grid>
                            <Grid.RowDefinitions>
                                <RowDefinition/>
                                <RowDefinition Height="Auto"/>
                            </Grid.RowDefinitions>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="Auto"/>
                                <ColumnDefinition/>
                            </Grid.ColumnDefinitions>
                            <TextBlock Text="🛑" Foreground="Red"
                                       Margin="0,0,4,0"
                                       Visibility="{x:Bind IsError}"/>
                            <TextBlock Grid.Column="2">
                                <Run FontWeight="Bold" Text="{x:Bind Type}"
                                     Foreground="{x:Bind local:MainPage.ColorSelector(TypeClass)}"/>
                                <Run Text="{x:Bind Text}"/>
                                <Run>[</Run><Run Text="{x:Bind SpanStart}"/>
                                <Run>..</Run><Run Text="{x:Bind SpanEnd}"/><Run>)</Run>
                            </TextBlock>
                            <TextBlock Text="{x:Bind ErrorText}"
                                       Visibility="{x:Bind IsError}"
                                       Grid.Row="2" Grid.ColumnSpan="2"
                                       Foreground="Red"/>
                        </Grid>
                    </muxc:TreeViewItem>
                </DataTemplate>
            </muxc:TreeView.ItemTemplate>
        </muxc:TreeView>

        <StackPanel Grid.Row="2" Margin="4,4,0,0">
            <TextBlock>
                <Run>Cursor Position Line: </Run>
                <Run Text="{x:Bind CurrentPosition.LineNumber, Mode=OneWay}"/>
                <Run> Col: </Run>
                <Run Text="{x:Bind CurrentPosition.Column, Mode=OneWay}"/>
            </TextBlock>
            <TextBlock Text="{x:Bind ElementInfo, Mode=OneWay}"/>
        </StackPanel>
    </Grid>
</Page>