Property Grid: Changing the SelectedObject causes memory leak

Start with the supplied MainWindow/Button_Click reproduction and the XAML PropertyGrid SelectedObject binding. Repeat the 2,000 object changes, force collection as shown, and inspect whether PropertyItem-related objects remain retained; done means repeated changes no longer leave the reported growing instances.

Hello;
I need help; PropertyGrid 4.4.0 in .NET6 WPF
Every time I change the SelectedObject the ManagedMemeory increases. e.g. in the example below I change the SelectedItem 2000x and the objects will never get collected.

What am I doing wrong; Thx.

Managed Memeory after 2000x changes                                     Count   Size   Inclusive size      
Xceed.Wpf.Toolkit.PropertyGrid.PropertyItemCollection	                4000	224000	9570840
List<Xceed.Wpf.Toolkit.PropertyGrid.PropertyItem>	                4000	240000	5577120
ObservableCollection<Xceed.Wpf.Toolkit.PropertyGrid.PropertyItem>	4000	224000	6313120
Xceed.Wpf.Toolkit.PropertyGrid.ObjectContainerHelper	                4000	291312	4223768
Xceed.Wpf.Toolkit.PropertyGrid.PropertyItem	                        2000	3764808	19228568
Xceed.Wpf.Toolkit.PropertyGrid.DescriptorPropertyDefinition	        2000	1952000	3007536

public partial class MainWindow : Window, INotifyPropertyChanged
{
    public MyModel SelectedItem { get; set; }
    public MyModel MyInstance1 { get; set; } = new MyModel();
    public MyModel MyInstance2 { get; set; } = new MyModel();
    public event PropertyChangedEventHandler? PropertyChanged;

    public MainWindow()
    {
        InitializeComponent();
        DataContext = this;
    }

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        for (int i = 0; i < 1000; i++)
        {
            SelectedItem = MyInstance1;
            SelectedItem = MyInstance2;
        }
        GC.Collect();
        GC.WaitForPendingFinalizers();
        GC.Collect();
    }
}

public class MyModel : INotifyPropertyChanged
{
    public string MyModelString { get; set; } = "testString";
    public event PropertyChangedEventHandler? PropertyChanged; 
}

 <Window x:Class="WpfApp1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:xctk="http://schemas.xceed.com/wpf/xaml/toolkit"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <StackPanel>
            <Button Click="Button_Click" Content="ClickMe"/>
            <xctk:PropertyGrid SelectedObject="{Binding SelectedItem}"/>
        </StackPanel>
    </Grid>
</Window>