[MVUX] Custom Control Style not set properly when bound to the model

[kucint]

Let´s create a simple Control:

internal class MyControl : Control
{
    public MyControl()
    {
        DefaultStyleKey = typeof(MyControl);
        Style = StyleFactory.CreateDefaultStyle();
    }
}

Style for this control is created dynamically as follows:

internal static class StyleFactory
{
    // Here we define the default UI of the control, it can also be change by user.
    public static Style<MyControl> CreateDefaultStyle() => new Style<MyControl>()
        .Setters(s => s
            .BorderBrush(Colors.Blue)
            .BorderThickness(1)
            .AutoUpdate(true)

            .Template(ctrl => new StackPanel()
                .BorderBrush(x => x.TemplateBind(() => ctrl.BorderBrush))
                .BorderThickness(x => x.TemplateBind(() => ctrl.BorderThickness))
                .Children(
                    new TextBlock().Text("default style"),
                    new TextBlock().Text(x => x.TemplateBind(() => ctrl.AutoUpdate))
                )
            )
        );

    public static Style<MyControl> CreateStyle(string txt, Color color) => new Style<MyControl>()
        .Setters(s => s
            .BorderBrush(color)
            .BorderThickness(3)
            .AutoUpdate(true)

            .Template(ctrl => new StackPanel()
                .BorderBrush(x => x.TemplateBind(() => ctrl.BorderBrush))
                .BorderThickness(x => x.TemplateBind(() => ctrl.BorderThickness))
                .Children(
                    new TextBlock().Text(txt),
                    new TextBlock().Text(x => x.TemplateBind(() => ctrl.AutoUpdate))
                )
            )
        );
}

Lest consume now the control and apply different styles to it:

public sealed partial class MainPage : Page
{
    public MainPage() => this
        .DataContext(new BindableMainPageModel(), (page, vm) => page
        .Background(ThemeResource.Get<Brush>("ApplicationPageBackgroundThemeBrush"))
        .Content(
            new StackPanel()
            .VerticalAlignment(VerticalAlignment.Center)
            .HorizontalAlignment(HorizontalAlignment.Center)
            .Children(
                new TextBlock()
                .Text("expected style: default style -> passed"),
                new MyControl()
                .Margin(0, 0, 0, 10),

                new TextBlock()
                .Text("expected style: style instantiated in the control -> passed"),
                new MyControl()
                .Style(StyleFactory.CreateStyle("style instantiated in the control", Colors.DarkOrchid))
                .Margin(0, 0, 0, 10),

                new TextBlock()
                .Text("expected style: style instantiated in the Frame -> passed"),
                new MyControl()
                .Margin(0, 0, 0, 10)
                .Style(new Style<MyControl>()
                    .Setters(s => s
                    .BorderBrush(Colors.DarkGreen)
                    .BorderThickness(5)
                    .AutoUpdate(true)
                    .Template(ctrl => new StackPanel()
                        .BorderBrush(x => x.TemplateBind(() => ctrl.BorderBrush))
                        .BorderThickness(x => x.TemplateBind(() => ctrl.BorderThickness))
                        .Children(
                            new TextBlock().Text("style instantiated in the Frame"),
                            new TextBlock().Text(x => x.TemplateBind(() => ctrl.AutoUpdate))
                        )
                    ))),

                new TextBlock()
                .Text("expected style: style instantiated in the model -> failed"),
                new MyControl()
                .Margin(0, 0, 0, 30)
                .Style(() => vm.Style),

                new TextBlock()
                .Text("expected style: style instantiated in the model (A, B, C) -> failed"),
                new ItemsControl()
                .ItemsSource(() => vm.Items)
                .ItemTemplate<Item>(item => new MyControl()
                    .Style(x => x.Binding(() => item.Style)))
                )
            )
        );
}

Model:

internal partial record MainPageModel
{
    public IState<Style> Style => State<Style>.Value(this, () => StyleFactory.CreateStyle("Style from model", Colors.HotPink));

    public IListState<Item> Items => ListState<Item>.Value(this, () =>
    [
        new Item("Item A", StyleFactory.CreateStyle("Style A from model", Colors.Red)),
        new Item("Item B", StyleFactory.CreateStyle("Style B from model", Colors.Green)),
        new Item("Item C", StyleFactory.CreateStyle("Style C from model", Colors.Blue)),
    ]);
}

internal record Item(string Name, Style Style);

In most of the cases, dynamically generated Style is applied as expected, but not when it comes from bound MVU model:

Tested on Windows: net8.0-desktop;

Note that when run on Windows with net8.0-windows10.0.19041; control does not render at all.
But this is another issue....

Uno version: "Uno.Sdk": "5.2.161"

Repro: UnoStyleAsPropertyApp.zip

Note that in the example above all styles are instantiated in the control so the static styles are nor created at all.
This is due to avoid interference with another issue #2349

[MartinZikmund]

This has been converted into an issue - #2400, let's continue the discussion there