MainWindow.axaml

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:oxy="clr-namespace:OxyPlot.Avalonia;assembly=OxyPlot.Avalonia"
        x:Class="Lab1.MainWindow"
        Title="Графики"
        Width="800" Height="600">

	<!-- TabControl, где каждая вкладка — отдельный PlotModel -->
	<TabControl ItemsSource="{Binding Plots}">
		<!-- Заголовок вкладки -->
		<TabControl.ItemTemplate>
			<DataTemplate>
				<TextBlock Text="{Binding Title}" />
			</DataTemplate> 
		</TabControl.ItemTemplate>

		<!-- Содержимое вкладки -->
		<TabControl.ContentTemplate>
			<DataTemplate>
				<oxy:PlotView Model="{Binding}"
							  Background="White"
							  HorizontalAlignment="Stretch"
							  VerticalAlignment="Stretch" />
			</DataTemplate>
		</TabControl.ContentTemplate>

	</TabControl>
</Window>