document view model not found when docking to floating window

Hi,

docking tool- and document- windows works fine in all scenarions except one:
see video below:

--- well, I don't know how I am supposed to attach a mp4 video file here ---

Neither cannot paste any image :(

in this scenario, the view model is not found. what is a reason of it?

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:vm="using:Ava.Actipro.BugDockedDocumentApp.ViewModels"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:actipro="http://schemas.actiprosoftware.com/avaloniaui"
        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
        x:Class="Ava.Actipro.BugDockedDocumentApp.Views.MainWindow"
        x:DataType="vm:MainWindowViewModel"
        Icon="/Assets/avalonia-logo.ico"
        Title="Ava.Actipro.BugDockedDocumentApp">

    <Design.DataContext>
        <!-- This only sets the DataContext for the previewer in an IDE,
             to set the actual DataContext for runtime, set the DataContext property in code (look at App.axaml.cs) -->
        <vm:MainWindowViewModel/>
    </Design.DataContext>

  <Window.Resources>
    <ControlTheme x:Key="DocumentWindowTheme" x:DataType="vm:DocumentViewModel" TargetType="actipro:DocumentWindow" BasedOn="{StaticResource {x:Type actipro:DocumentWindow}}">

      <!-- DockingWindow (BaseType) -->
      <Setter Property="Description" Value="{Binding Description, Mode=TwoWay}" />
      <Setter Property="Icon" Value="{Binding Icon, Mode=TwoWay}" />
      <Setter Property="IsFloating" Value="{Binding IsFloating, Mode=TwoWay}" />
      <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
      <Setter Property="SerializationId" Value="{Binding SerializationId, Mode=TwoWay}" />
      <Setter Property="Title" Value="{Binding Title, Mode=TwoWay}" />
      <Setter Property="WindowGroupName" Value="{Binding WindowGroupName, Mode=TwoWay}" />
      <Setter Property="CanClose" Value="{Binding CanClose, Mode=TwoWay}" />
      <Setter Property="CanFloat" Value="{Binding CanFloat, Mode=TwoWay}" />

      <!-- IMPORTANT: These properties should be configured last so that other bindings are applied before the window opens -->
      <Setter Property="IsActive" Value="{Binding IsActive, Mode=TwoWay}" />
      <Setter Property="IsOpen" Value="{Binding IsOpen, Mode=TwoWay}" />

    </ControlTheme>
  </Window.Resources>

  <!-- NOTE: The implicit DataTemplates defined here should normally be placed in Application.Resources so that they will be found by floating windows -->
  <Window.DataTemplates>
    <DataTemplate DataType="{x:Type vm:DocumentAViewModel}">
      <TextBox Text="This is Document A" Margin="5"/>
    </DataTemplate>
    <DataTemplate DataType="{x:Type vm:DocumentBViewModel}">
      <TextBox Text="This is Document B" Margin="5"/>
    </DataTemplate>
  </Window.DataTemplates>

  <actipro:DockSite x:Name="MainDockSite"
                    DocumentItemsSource="{Binding Documents}"
                    DocumentItemContainerTheme="{StaticResource DocumentWindowTheme}">
    <actipro:SplitContainer Orientation="Horizontal">
      <!-- Left panel with Node Library -->

      <actipro:ToolWindowContainer MinWidth="112" MinHeight="0">
        <actipro:ToolWindow Title="Node Library" ContainerDockedSize="286, 300">
          <TextBox Text="Node Library" Margin="5"/>
        </actipro:ToolWindow>
      </actipro:ToolWindowContainer>

      <!-- Main Workspace and Bottom Panel -->
      <actipro:SplitContainer Orientation="Vertical">
        <!-- Main Workspace -->
        <actipro:Workspace>
          <actipro:TabbedMdiHost/>
        </actipro:Workspace>
        <!-- Bottom panel with Node Info and Log Viewer -->
        <actipro:ToolWindowContainer>
          <!--<actipro:ToolWindow Title="Node Info"/>-->
          <actipro:ToolWindow Title="Log Viewer">
            <TextBox Text="Log Viewer" Margin="5"/>
          </actipro:ToolWindow>
        </actipro:ToolWindowContainer>
      </actipro:SplitContainer>
    </actipro:SplitContainer>
  </actipro:DockSite>
</Window>

Suggestion:
maybe " <!-- NOTE: The implicit DataTemplates defined here should normally be placed in Application.Resources so that they will be found by floating windows -->" is the issue?

I tried to move the document templates to App, but it did not solve the problem.

I attach full source code of test app to easely repro the issue:

--- well, I don't know how I am supposed to attach a zip file here ---