presence/Presence.Desktop/Views/MainWindow.axaml

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:vm="using:Presence.Desktop.ViewModels"
        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="Presence.Desktop.Views.MainWindow"
        Icon="/Assets/avalonia-logo.ico"
        Title="Presence.Desktop"
        x:DataType="vm:MainWindowViewModel">

	<Design.DataContext>
		<vm:MainWindowViewModel/>
	</Design.DataContext>

	<DockPanel Background="White">
		<StackPanel Height="30" DockPanel.Dock="Bottom" Background="White">
			<TextBlock Text="List ↑" HorizontalAlignment="Center" Margin="5">
			</TextBlock>
		<StackPanel/>
		</StackPanel>
		<!-- Верхняя панель -->
		<StackPanel DockPanel.Dock="Top" Orientation="Horizontal" HorizontalAlignment="Center" Background="White" Height="40">
			<TextBlock Text="Combobox →" HorizontalAlignment="Center" Margin="10">
			</TextBlock>
			<ComboBox  Margin="5"/>
			<ComboBox  Margin="5"/>
			<ComboBox  Margin="5"/>
		</StackPanel>
		<StackPanel Background="Beige"/>
	</DockPanel>

</Window>