Avalonia/samples/VirtualizationDemo/MainWindow.axaml

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:controls="using:ControlSamples"
        xmlns:vm="using:VirtualizationDemo.ViewModels"
        xmlns:views="using:VirtualizationDemo.Views"
        x:Class="VirtualizationDemo.MainWindow"
        Title="AvaloniaUI Virtualization Demo"
        Width="800"
        Height="600"
        x:DataType="vm:MainWindowViewModel">
  <controls:HamburgerMenu>
    <TabItem Header="Chat" >
      <views:ChatPageView DataContext="{Binding Chat}"/>
    </TabItem>
  </controls:HamburgerMenu>
</Window>