Avalonia/samples/ControlCatalog/Pages/WindowCustomizationsPage.xaml

<UserControl xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
             x:Class="ControlCatalog.Pages.WindowCustomizationsPage">
  <StackPanel Spacing="10"  Margin="25">
    <CheckBox Content="Extend Client Area to Decorations" IsChecked="{Binding ExtendClientAreaEnabled}" />
    <CheckBox Content="Title Bar" IsChecked="{Binding SystemTitleBarEnabled}" />    
    <CheckBox Content="Prefer System Chrome" IsChecked="{Binding PreferSystemChromeEnabled}" />
    <Slider Minimum="-1" Maximum="200" Value="{Binding TitleBarHeight}" />
    <ComboBox x:Name="TransparencyLevels" SelectedIndex="{Binding TransparencyLevel}">
      <ComboBoxItem>None</ComboBoxItem>
      <ComboBoxItem>Transparent</ComboBoxItem>
      <ComboBoxItem>Blur</ComboBoxItem>
      <ComboBoxItem>AcrylicBlur</ComboBoxItem>
      <ComboBoxItem>Mica</ComboBoxItem>
    </ComboBox>
  </StackPanel>
</UserControl>