QWebEngineView freezes while autoscrolling a web page

[lmofallis]

I'm using C++ with Qt v5.9.1.
I'm dealing with a problem when I use QWebEngineView. It freezes in the AutoScrolling, then it unfreezes and returns to normal after the AutoScrolling finish.

Freezes:

void MainWindow::on_BTN_Load_clicked()
{
    QUrl url = QUrl(ui->lineEdit->text());
    webview->page()->load(url);
    connect(webview->page(), &QWebEnginePage::loadFinished, this, &MainWindow::on_PageLoadFinished);
}

void MainWindow::on_PageLoadFinished()
{
    disconnect(webview->page(), &QWebEnginePage::loadFinished, this, &MainWindow::on_PageLoadFinished);

    //Get the page's height
    webview->page()->runJavaScript("document.body.scrollHeight",[&](const QVariant &result) {set_PageHeight(result.toInt());});
}

void MainWindow::set_PageHeight(int TheHeight)
{
    ThePageHeight = TheHeight;
    ScrollDownPage();
}

void MainWindow::ScrollDownPage()
{
    TheCurrentVerticalScroll = 0;

    while (TheCurrentVerticalScroll <= ThePageHeight)
    {
        webview->page()->runJavaScript(QString("window.scrollTo(0, %1);").arg(TheCurrentVerticalScroll));
        TheCurrentVerticalScroll += 100;

        QEventLoop loop;
        QTimer t;
        t.connect(&t, &QTimer::timeout, &loop, &QEventLoop::quit);
        t.start(30);
        loop.exec();
        qApp->processEvents();
    }
}

Works:
But, this problem doesn't appear when I click manually on a button that call the same AutoScrolling function.

void MainWindow::on_BTN_Load_clicked()
   {
       QUrl url = QUrl(ui->lineEdit->text());
       webview->page()->load(url);
       connect(webview->page(), &QWebEnginePage::loadFinished, this, &MainWindow::on_PageLoadFinished);
   }

   void MainWindow::on_PageLoadFinished()
   {
       disconnect(webview->page(), &QWebEnginePage::loadFinished, this, &MainWindow::on_PageLoadFinished);

       //Get the page's height
       webview->page()->runJavaScript("document.body.scrollHeight",[&](const QVariant &result) {set_PageHeight(result.toInt());});
   }

   void MainWindow::set_PageHeight(int TheHeight)
   {
       ThePageHeight = TheHeight;
       // ScrollDownPage();     //I disable this now
   }

   void MainWindow::ScrollDownPage()
   {
       TheCurrentVerticalScroll = 0;

       while (TheCurrentVerticalScroll <= ThePageHeight)
       {
           webview->page()->runJavaScript(QString("window.scrollTo(0, %1);").arg(TheCurrentVerticalScroll));
           TheCurrentVerticalScroll += 100;

           QEventLoop loop;
           QTimer t;
           t.connect(&t, &QTimer::timeout, &loop, &QEventLoop::quit);
           t.start(30);
           loop.exec();
           qApp->processEvents();
       }
   }

  //I add this:
   void MainWindow::on_BTN_Scroll_clicked()
   {
       ScrollDownPage();
   }

What I want:

I want to scroll the web page automatically, not manually by clicking the button.
Thanks.

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These is my code:
https://drive.google.com/drive/folders/0ByYSO6K4jXdgZmQxd3pXVG90dVU?usp=sharing