Avalonia/samples/IntegrationTestApp/ShowWindowTest.axaml

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        x:Class="IntegrationTestApp.ShowWindowTest"
        Name="SecondaryWindow"
        Title="Show Window Test">
  <Grid ColumnDefinitions="Auto,Auto" RowDefinitions="Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto">
    <Label Grid.Column="0" Grid.Row="1">Client Size</Label>
    <TextBox Name="ClientSize" Grid.Column="1" Grid.Row="1" IsReadOnly="True"
             Text="{Binding ClientSize, Mode=OneWay}"/>
    
    <Label Grid.Column="0" Grid.Row="2">Frame Size</Label>
    <TextBox Name="FrameSize" Grid.Column="1" Grid.Row="2" IsReadOnly="True"
             Text="{Binding FrameSize, Mode=OneWay}"/>

    <Label Grid.Column="0" Grid.Row="3">Position</Label>
    <TextBox Name="Position" Grid.Column="1" Grid.Row="3" IsReadOnly="True"/>

    <Label Grid.Column="0" Grid.Row="4">Owner Rect</Label>
    <TextBox Name="OwnerRect" Grid.Column="1" Grid.Row="4" IsReadOnly="True"/>
    
    <Label Grid.Column="0" Grid.Row="5">Screen Rect</Label>
    <TextBox Name="ScreenRect" Grid.Column="1" Grid.Row="5" IsReadOnly="True"/>

    <Label Grid.Column="0" Grid.Row="6">Scaling</Label>
    <TextBox Name="Scaling" Grid.Column="1" Grid.Row="6" IsReadOnly="True"/>
    
    <Label Grid.Column="0" Grid.Row="7">WindowState</Label>
    <ComboBox Name="WindowState" Grid.Column="1" Grid.Row="7" SelectedIndex="{Binding WindowState}">
      <ComboBoxItem>Normal</ComboBoxItem>
      <ComboBoxItem>Minimized</ComboBoxItem>
      <ComboBoxItem>Maximized</ComboBoxItem>
      <ComboBoxItem>Fullscreen</ComboBoxItem>
    </ComboBox>
    <Button Name="HideButton" Grid.Row="8" Command="{Binding $parent[Window].Hide}">Hide</Button>
  </Grid>
</Window>