SelectedItem setter is triggered for unchanged value in SelectingItemsControl

[jp2masa]

Repro

<ComboBox Items="{Binding Items}" SelectedItem="{Binding SelectedItem}" />

class ViewModel : ReactiveObject
{
    private string _selectedItem = "4";

    public IEnumerable<string> Items { get; } = Enumerable.Range(0, 5).Select(i => i.ToString()).ToArray();

    public string SelectedItem
    {
        get => _selectedItem;
        set => this.RaiseAndSetIfChanged(ref _selectedItem, value); // breakpoint here
    }
}

The breakpoint will be triggered on initialization, even though the selected item is correct and exists on Items.

Problem

The problem is comparing by reference here: https://github.com/AvaloniaUI/Avalonia/blob/master/src/Avalonia.Base/Data/Core/SettableNode.cs#L45.

Replacing Object.ReferenceEquals with Object.Equals works as expected, but I'm not sure if this would be the correct behavior.

[MrJul]

Fixed by #13970