Unable to see tools added programatically after deserialization.

[sboutin4]

First of all, thank you for creating this library, it's very useful!

I'm experiencing an issue where I'm unable to see the tools I add programmatically after de-serialization. I can use the dock factory features just fine, I can save and load the layout and I can add tools with this method:

public void AddTool(ITool tool)
{
    if (_toolDock is null)
    {
        return;
    }
    
    AddDockable(_toolDock, tool);
    SetActiveDockable(tool);
    SetFocusedDockable(_toolDock, tool);
}

A user in #344 mentions having issues just creating the tools. It's working fine for me before serialization. However, using this method after de-serialization, the new tools are nowhere to be found. The _toolDock is re-created properly within the layout, I can clearly see that the new tools are added to its VisibleDockables along with the de-serialized tools, but these new tools don't show up. There's no tab created for them.

The layout is serialized using the DockSerializer, if that matters.

_dockSerializer = new DockSerializer(typeof(AvaloniaList<>));

The CreateLayout method looks like this:

public override IRootDock CreateLayout()
{
    var toolDock = new ToolDock
    {
        Id = ToolDockId,
        VisibleDockables = CreateList<IDockable>()
    };
    
    var dashboardDock = CreateRootDock();
    dashboardDock.Id = DashboardId;
    dashboardDock.ActiveDockable = toolDock;
    dashboardDock.DefaultDockable = toolDock;
    dashboardDock.VisibleDockables = CreateList<IDockable>(toolDock);
    dashboardDock.IsCollapsable = false;
    
    var rootDock = CreateRootDock();
    rootDock.Id = RootDockId;
    rootDock.ActiveDockable = dashboardDock;
    rootDock.DefaultDockable = dashboardDock;
    rootDock.VisibleDockables = CreateList<IDockable>(dashboardDock);
    rootDock.IsCollapsable = false;
    
    _toolDock = toolDock;
    _dashboardDock = dashboardDock;
    _rootDock = rootDock;
    
    return rootDock;
}

And the InitLayout looks like that:

public override void InitLayout(IDockable layout)
{
    DockableLocator = new Dictionary<string, Func<IDockable?>>
    {
        [RootDockId] = () => _rootDock,
        [DashboardId] = () => _dashboardDock,
        [ToolDockId] = () => _toolDock
    };
    ContextLocator = new Dictionary<string, Func<object?>>();
    HostWindowLocator = new Dictionary<string, Func<IHostWindow?>>
    {
        [nameof(IDockWindow)] = () =>
        {
            var hostWindow = new HostWindow
            {
                [!Window.TitleProperty] = new Binding(TitleBindingPath)
            };
            return hostWindow;
        }
    };

    base.InitLayout(layout);
}

I was able to reproduce this in the DockMvvmSample project after adding layout serialization. Any idea what's going on? This feels like a bug in the library but I'm probably missing something.