Programmatically add a document to a DocumentDock. The document content is an usercontrol with datagrid

[dariocigna]

I successfully added a document containing an usercontrol to a DocumentControl in XAML

this is the Usercontrol View

<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"
			 xmlns:vm="clr-namespace:ClientWOMAvalonia.ViewModels"
			 xmlns:local="using:ClientWOMAvalonia"
             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
             x:Class="ClientWOMAvalonia.Views.GridControlView"
			 x:DataType="vm:GridControlViewModel"
			 			 
			 >
	<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:GridControlViewModel />
		
	</Design.DataContext>

	
		<Grid x:Name="grid" RowDefinitions="Auto,*">
			<DataGrid x:Name="WomGrid" Grid.Row="0" AutoGenerateColumns="False">
				<DataGrid.Columns>
					<DataGridTextColumn Header="Forename" Binding="{Binding FirstName}"/>
					<DataGridTextColumn Header="Surname" Binding="{Binding LastName}" />
				</DataGrid.Columns>
			</DataGrid>
			
		</Grid>

</UserControl>

this is the main view

<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"
             xmlns:vm="clr-namespace:ClientWOMAvalonia.ViewModels"
			 
			 xmlns:i="using:Avalonia.Interactivity"
			 xmlns:id="using:Dock.Avalonia"
             xmlns:dm="using:Dock.Model.Core"
             
			 xmlns:dmc="using:Dock.Avalonia.Controls"
             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
             x:Class="ClientWOMAvalonia.Views.MainView"
             x:DataType="vm:MainViewModel"
			 xmlns:views="clr-namespace:ClientWOMAvalonia.Views"			 
			 x:CompileBindings="True"
			 >
  <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:MainViewModel />
	
  </Design.DataContext>
	
	<Grid RowDefinitions="Auto,*">

		<Menu Grid.Row="0">
			<MenuItem Header="_File">
				<MenuItem x:Name="FileOpenLayout" Header="_Connect..." Command="{Binding ConnectToServerCommand}" CommandParameter="pippo" />
				<Separator/>
				<MenuItem x:Name="FileSaveLayout" Header="_Save layout..."/>
				<Separator/>
				<MenuItem x:Name="FileCloseLayout" Header="_Close layout" />
			</MenuItem>
		</Menu>

		<SplitView Grid.Row="1" IsPaneOpen="True"
           DisplayMode="Inline"
           OpenPaneLength="296">
			<SplitView.Pane>
				<ListBox SelectionMode="Single" Selection="{Binding Selection}" ItemsSource="{Binding Classes}">
					<ItemsControl.ItemTemplate>
						<DataTemplate>
							
							
							<TextBlock HorizontalAlignment="Left" Text="{Binding DisplayedName}">
								<Button Command="{Binding $parent.$parent.SelectClassCommand}"></Button>
							</TextBlock>
									   
									  
						</DataTemplate>
					</ItemsControl.ItemTemplate>
					
					
				</ListBox>
			</SplitView.Pane>

			<Grid>
				<DockControl x:Name="Dock" Grid.Row="1" InitializeLayout="True" InitializeFactory="True">
					<DockControl.Factory>
						<Factory />
					</DockControl.Factory>

					<RootDock x:Name="Root" Id="Root" IsCollapsable="False" DefaultDockable="{Binding #MainLayout}">

						<!-- Windows -->

						<RootDock.Windows>
			
						</RootDock.Windows>

						<ProportionalDock x:Name="MainLayout" Id="MainLayout" Orientation="Horizontal">


							<!-- Top Pane -->

							<ProportionalDock x:Name="TopPane" Id="TopPane" Orientation="Vertical">

								<DocumentDock x:Name="DocumentsPane" Id="DocumentsPane" CanCreateDocument="True" ActiveDockable="Document1">

									<Document x:Name="Document1" Id="Document1" Title="App.axaml" x:DataType="Document">
										
											<views:GridControlView/>
										
									</Document>
									
									
								</DocumentDock>
								

							</ProportionalDock>

						</ProportionalDock>
					</RootDock>

				</DockControl>

			</Grid>
		</SplitView>

	
	</Grid>
	

</UserControl>

Now i would like to add a new GridControl to a new document programmatically.

I successfully added tabs with correct titles

            var document = new GridControlViewModel { Id = $"Document{index}", Title = $"Document{index}" };
           DocumentsPane.VisibleDockables.Add(document);

but whatever i do the content of new document is always empty

notes:
checking the new document parent i see it's: {Dock.Avalonia.Controls.DocumentTabStripItem}
instead the parent of existing document build in xaml is:{Avalonia.Controls.ContentControl}

(if i set the content of the new document = content of existing xaml document it shows correctly)