MenuFlyout ItemTemplate not Applied

[workgroupengineering]

To Reproduce
Steps to reproduce the behavior:

1. Download Attach
2. Extract
3. Open
4. Run
5. Click on DropDownButton
6. You Can se error

Expected behavior
ItemTemplate is applied

Screenshots
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Desktop (please complete the following information):

• OS: [e.g. Windows, Mac, Linux (State distribution)]
• Version: 11.0.0-preview4

Additional context
Add any other context about the problem here.

DropDownButton_Issue.zip

[rabbitism]

Maybe duplicate with mine #9696

[workgroupengineering]

Duplicated

[workgroupengineering]

After some thorough investigation the problem is similar but not the same of #9696.

[FG-rgb]

Fix does not work with Avalonia 11.0.0-preview5.
Now it is complete broken and shows no items:
[Binding]Error in binding to 'Avalonia.Controls.MenuFlyout'.'Items': 'Null value in expression '{empty}' at ''.'(MenuFlyout #5560998)

My Window xaml looks like this:

<Button Content="Testen">
    <Button.Flyout>
	    <MenuFlyout Placement="Left" Items="{Binding Path=TestItems,Mode=OneWay}">
		    <MenuFlyout.ItemTemplate>
			    <DataTemplate>
				    <TextBlock Text="{Binding Path=Name,Mode=OneWay}" />
			    </DataTemplate>
		    </MenuFlyout.ItemTemplate>
	    </MenuFlyout>
    </Button.Flyout>
</Button>

And the ViewModel looks like this:

public record class TestItem(string Name, string Info);

public class MainWindowViewModel
{
    public MainWindowViewModel()
    {
        TestItems = new ObservableCollection<TestItem>
        {
            new TestItem("Hallo", "Hallo Welt"),
            new TestItem("Bla", "Hallo Welt"),
            new TestItem("Blubb", "Hallo Welt"),
            new TestItem("Etwas mehr Text", "Hallo Welt"),
            new TestItem("Hallo Ihr da", "Hallo Welt")
        };
    }

    public ObservableCollection<TestItem> TestItems { get; }

With Avalonia 0.10.18 the items are plain shown in UI as ToString()

[timunie]

@FG-rgb please open this as a new issue. Closed issues will not be followed up. Also your issue seems to be different to the one posted above.

[FG-rgb]

Ok @timunie bug created:
#10626