[Bug]: Custom DI container with RxUI - Unable to resolve type IValidationTextFormatter

Prerequisites

• I have searched open and closed issues for duplicates.
• I am using the latest stable release.

Describe the bug 🐞

With ReactiveUI and Avalonia, I'm following the documentation to use my own DI container with a custom IDependencyResolver implementation and the AppBuilder extension .UseReactiveUIWithDIContainer().

I'm receiving the an InvalidOperationException when trying to resolve ReactiveUI.Validation.Formatters.Abstractions.IValidationTextFormatter`1[System.String]. The Validation classes are not registered into my container through my resolver. They are registered in the original Splat container before AppLocator.SetLocator(dependencyResolver) switches. What's the correct way to resolve this?

Steps to reproduce

using LightInject;

internal class Program
{
    private static ServiceContainer _container;

    [STAThread]
    public static void Main(string[] args)
    {
        _container = RegisterContainer();
        var builder = BuildAvaloniaApp();
        builder.StartWithClassicDesktopLifetime(args);
    }

    public static AppBuilder BuildAvaloniaApp()
        => AppBuilder.Configure(static () => new App(_container))
            .UsePlatformDetect()
            .WithInterFont()
            .LogToTrace()
            .UseReactiveUIWithDIContainer(() => _container,
                                          x => { },
                                          c => new LightInjectResolver(c),
                                          x =>
                                          {
                                              x.WithExceptionHandler(new RootExceptionHandler());
                                          });
}

Reproduction repository

No response

Expected behavior

I would have expected an instance of ReactiveUI.Validation.Formatters.Abstractions.IValidationTextFormatter`1[System.String] to be automatically registered through my IDependencyResolver implementation. Or alternatively, a method to register RxUI.Validation types manually

Screenshots 🖼️

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IDE

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.NET version

.NET 10

Target framework(s)

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Operating system

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OS version

No response

Device

No response

ReactiveUI version

ReactiveUI.Validation=7.1.0, ReactiveUI.Avalonia=12.0.3

Additional information ℹ️

No response

Trace the UseReactiveUIWithDIContainer entry point and the AppLocator.SetLocator transition, then inspect how ReactiveUI.Validation formatter types are registered and resolved through IDependencyResolver. Reproduce the LightInject setup and verify whether IValidationTextFormatter resolves through the custom container or requires a supported manual-registration path.