private MainWindow(Builder builder) : base(builder.GetObject(nameof(MainWindow)).Handle)
{
builder.Autoconnect(this);
var r = new DictionaryVisualResolver <GtkTritonPage>();
_resolver = new TestFvr(r);
DeleteEvent += (_, e) => Application.Quit();
_viewModel.PageAdded += AddVisualPage;
_viewModel.PageClosed += CloseVisualPage;
r.RegisterVisual <TestViewModel, TestPage>();
_viewModel.AddPage(new TestViewModel());
_viewModel.AddPage(new TestViewModel());
_viewModel.AddPage(new TestViewModel());
}