WpfVirtualizedTreeViewPerItemVisibilitySO3.xaml

<Window x:Class="WpfVirtualizedTreeViewPerItemVisibility.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        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"
        xmlns:local="clr-namespace:WpfVirtualizedTreeViewPerItemVisibility"
        mc:Ignorable="d"
        Title="MainWindow" Height="400" Width="600">
    <Window.Resources>
        <HierarchicalDataTemplate DataType="{x:Type local:TvItemType1}" ItemsSource="{Binding FilteredEntries}">
            <TextBlock Text="{Binding Name1}" />
            <HierarchicalDataTemplate.ItemContainerStyle>
                <Style TargetType="TreeViewItem">
                    <Setter Property="IsExpanded" Value="True" />
                </Style>
            </HierarchicalDataTemplate.ItemContainerStyle>
        </HierarchicalDataTemplate>
        <HierarchicalDataTemplate DataType="{x:Type local:TvItemType2}">
            <TextBlock Text="{Binding Name2}" />
        </HierarchicalDataTemplate>
    </Window.Resources>
    <Grid>
        <ToggleButton Content="A" IsChecked="{Binding ShowA, Mode=TwoWay}" Width="20" Height="20" HorizontalAlignment="Left" VerticalAlignment="Top" />
        <TreeView x:Name="tv"
                  ScrollViewer.VerticalScrollBarVisibility="Visible"
                  ScrollViewer.CanContentScroll="True"
                  VirtualizingStackPanel.IsVirtualizing="True"
                  VirtualizingStackPanel.VirtualizationMode="Standard" Margin="0,24,0,0" />
    </Grid>
</Window>