QtWebEngine flashes when the frameless window is maximized

#include <QWidget>
 #include <QHBoxLayout>
 #include <QApplication>
 #include <QWebEngineView>
 
 int main(int argc, char *argv[])
 {
 QApplication app(argc, argv);
 QWidget* widget = new QWidget(0);
 widget->setWindowFlags(Qt::FramelessWindowHint);
 QHBoxLayout* lay_parent = new QHBoxLayout;
 QWebEngineView *webView = new QWebEngineView;
 webView->load(QUrl("https://qt.io"));
 widget->show();
 lay_parent->addWidget(webView);
 widget->setLayout(lay_parent);
 widget->showMaximized();
 return app.exec();
 }

QCoreApplication::setAttribute(Qt::AA_UseOpenGLES);

QCoreApplication::setAttribute(Qt::AA_UseSoftwareOpenGL);