Datatable with no data when is inside a TabPane

[Salvodif]

Hi,
I don't know why my datatable is displayed empty.
I debugged and everything seems to work fine.
Maybe I need to call some refresh? I don't see any method that can do something like this

class LibraryApp(App):
    CSS_PATH = "styles.tcss"


    def __init__(self, config_path: str, **kwargs):
        super().__init__(**kwargs)
        self.config_path = config_path
        self.library_manager = None
        self.cache_books = []

    def load_config(self):
        config = ConfigParser()
        config.read(self.config_path)
        self.library_path = config.get("Settings", "librarypath", fallback="library.json")
        self.library_manager = BibliothecaProcurator(self.library_path)

    def compose(self) -> ComposeResult:
        yield Header()
        
        yield Static(
            "📚 **LibraryApp** - Gestione Libri 📖",
            id="app_title",
        )

        with TabbedContent():
            with TabPane("Libreria"):
                # yield Vertical(
                #         Horizontal(
                #             Input(placeholder="Cerca libri... (minimo 3 caratteri)", id="search_input"),
                #             Button("Cerca", id="search_button", disabled=True),
                #             id="search_container"
                #         ),
                yield DataTable(id="output", cursor_type="row", zebra_stripes=True)
                # , id="main_container"
                    # )
            with TabPane("Aggiungi Libro"):
                yield Vertical(
                    Static("Inserisci i dettagli del libro:"),
                    Input(placeholder="Titolo", id="add_title"),
                    Input(placeholder="Autore", id="add_author"),
                    Input(placeholder="Tags (separati da virgola)", id="add_tags"),
                    Button("Aggiungi", id="submit_add"),
                    id="add_book_form"
                )

        yield Footer()

    async def on_mount(self):
        self.load_config()
        await self.view_books()

    async def view_books(self):
        try:
            output_widget = self.query_one("#output", DataTable)
        except Exception as e:
            self.notify("Errore nel recupero della tabella")
            return
    
        if not self.cache_books:
            self.cache_books = self.library_manager.get_all_books_sorted_by_date()

        # Cancella i dati esistenti nella tabella
        output_widget.clear()
        
        if not self.cache_books:
            output_widget.add_columns("Messaggio")
            output_widget.add_row("Nessun libro trovato")
            return

        # Aggiungi le colonne alla tabella
        output_widget.add_columns("Titolo", "Autore", "Aggiunto in data")

        # Aggiungi i libri alla tabella
        for book in self.cache_books:
            output_widget.add_row(
                book["title"],
                book["author"],
                book["created_at"],
                key=book["uuid"])