Empty dialog content's visuals

I’ve written a simple program with avalonia’s mvvm template. Here’s my MainWindowView.xaml code:

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:vm="using:DialogHostTest.ViewModels"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:dialogHost="clr-namespace:DialogHost;assembly=DialogHost.Avalonia"
        mc:Ignorable="d"
        Width="300"
        Height="200"
        x:Class="DialogHostTest.Views.MainWindow"
        Icon="/Assets/avalonia-logo.ico"
        Title="DialogHostTest">

    <Design.DataContext>
        <vm:MainWindowViewModel/>
    </Design.DataContext>

  <dialogHost:DialogHost Identifier="{Binding DialogHostId}">
    <Button VerticalAlignment="Stretch"
            HorizontalAlignment="Stretch"
            VerticalContentAlignment="Center"
            HorizontalContentAlignment="Center"
      Content="Show dialog" Command="{Binding ShowDialogAsync}"/>
    
  </dialogHost:DialogHost>

</Window>

And here’s MainViewModel’s code:

using System.Threading.Tasks;

namespace DialogHostTest.ViewModels
{
    public class MainWindowViewModel : ViewModelBase
    {
        public static string DialogHostId => "MainDialogHost";

        public async Task ShowDialogAsync()
        {
            var result = await MessageBoxViewModel.ShowAsync("Test message!", DialogHostId);
        }
    }
}

I want to show message box on this button’s click, so I wrote a simple UserControl and ViewModel for it.

View’s code:

<UserControl xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             mc:Ignorable="d"
             x:Class="DialogHostTest.Views.MessageBoxView">

  <Grid RowDefinitions="*,10,*"
        ColumnDefinitions="*,10,*">
    <TextBlock Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="3"
               Text="{Binding Message}"/>
    <Button Grid.Row="2" Grid.Column="0"
            Content="OK"
            Command="{Binding OkButton}"/>
    <Button Grid.Row="2" Grid.Column="2"
            Content="Cancel"
            Command="{Binding CancelButton}"/>
  </Grid>

</UserControl>

ViewModel’s code:

using System.Threading.Tasks;
using ReactiveUI;
using DialogHostTest.Enums;

namespace DialogHostTest.ViewModels
{
    public class MessageBoxViewModel : ViewModelBase
    {
        private string _message;

        public string Message 
        {
            get => _message;
            set => this.RaiseAndSetIfChanged(ref _message, value);
        }

        public DialogResult DialogResult { get; set; }

        public MessageBoxViewModel(string message)
        {
            Message = message;
        }

        public void OkButton()
        {
            DialogResult = DialogResult.OK;

            CloseDialog(MainWindowViewModel.DialogHostId);
        }

        public void CancelButton()
        {
            DialogResult = DialogResult.Cancel;

            CloseDialog(MainWindowViewModel.DialogHostId);
        }

        public void CloseDialog(string dialogHostId)
        {
            DialogHost.DialogHost.Close(dialogHostId, DialogResult);
        }
    
        public static async Task<DialogResult> ShowAsync(string message, string dialogHostId)
        {
            var res = await DialogHost.DialogHost.Show(new MessageBoxViewModel(message), dialogHostId);

            return (DialogResult)res;
        }
    }
}

But when I click on the button, I can’t see the desired UserControl:

That’s how it looks in VS’s designer:

Though I must say, that when I click on areas, where buttons should be, the dialog closes successfully, and I receive desired DialogResult.

[SKProCH]

I think this is a bug and I’m writing a fix right now. But in general, yes, you can fix it yourself.

[SKProCH]

Sorry for the long answer.

I will try to take the time and fix it soon.