QTableWidget Unknown Tab Operation After hide() and show()

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QTimer> 
#include <Windows.h> 

MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent),

ui(new Ui::MainWindow)
{
        ui->setupUi(this);     
        ui->tableWidget->setRowCount(3);
        ui->tableWidget->setColumnCount(3); 

        QTimer *refresh = new QTimer(this);
        connect(refresh, &QTimer::timeout, this, &MainWindow::on_RefreshTable);
        refresh->start(1000);
} 

MainWindow::~MainWindow()
{      
        delete ui;
}

void MainWindow::on_RefreshTable()
{
        ui->tableWidget->hide();
        Sleep(200);
        ui->tableWidget->show();
}