ChatPage.xaml

<Page x:Class="DotPilot.Presentation.ChatPage"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:controls="using:DotPilot.Presentation.Controls"
      Background="Transparent"
      FontFamily="{StaticResource AppBodyFontFamily}">
  <Grid AutomationProperties.AutomationId="ChatScreen"
        MaxWidth="1380"
        RowSpacing="16">
    <Grid.RowDefinitions>
      <RowDefinition Height="Auto" />
      <RowDefinition Height="*" />
    </Grid.RowDefinitions>

    <Grid AutomationProperties.AutomationId="ChatScreenHeader">
      <StackPanel Spacing="4">
        <TextBlock AutomationProperties.AutomationId="ChatPageTitle"
                   FontSize="24"
                   FontWeight="SemiBold"
                   Text="Chat" />
        <TextBlock FontSize="12.5"
                   Foreground="{StaticResource AppMutedTextBrush}"
                   Text="Sessions, transcript, and live activity."
                   TextWrapping="WrapWholeWords" />
      </StackPanel>
    </Grid>

    <Grid Grid.Row="1"
          AutomationProperties.AutomationId="ChatLayout"
          ColumnSpacing="16"
          RowSpacing="16">
      <Grid.ColumnDefinitions>
        <ColumnDefinition Width="272" />
        <ColumnDefinition Width="*" />
        <ColumnDefinition Width="296" />
      </Grid.ColumnDefinitions>

      <controls:ChatSessionRail />

      <Grid Grid.Column="1"
            RowSpacing="18">
        <Grid.RowDefinitions>
          <RowDefinition Height="*" />
          <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>

        <controls:ChatConversationView />
        <controls:ChatComposer Grid.Row="1"
                               Tag="{Binding ComposerSendBehavior}" />
      </Grid>

      <controls:ChatInfoPanel Grid.Column="2" />
    </Grid>
  </Grid>
</Page>