table headers disappear when using collapsible table rows.

  public static function getTableColumns()
    {
        return [
            Split::make([
                TextColumn::make('status')
                    
                TextColumn::make('invoice_nbr')->label('Invoice number')->sortable(),
                TextColumn::make('transaction_date')->sortable()
                    ->date('n/j/Y'),
                TextColumn::make('transactionType.name')
                    ->badge()
                  
                   )->sortable(),
                TextColumn::make('po_nbr')->label('PO number'),
                TextColumn::make('original_amount')->formatStateUsing(fn ($state) => '$' . number_format($state / 100, 2))
                   
                    ])->sortable(),
                TextColumn::make('balance')->formatStateUsing(fn ($state) => '$' . number_format($state / 100, 2))
                  
                    ])->sortable()
            ]),
            Panel::make([
...collapsible stuff...
])
];
}