QWebEngineView window won't show

[freethewall]

I wrote a simple test program to load a URL in a QWebEngineView. The program works on Mac; the browser pops up and I can see the webpage. But on Windows 7, the browser window never appears after I call show():

import sys

from PyQt5.QtWidgets import QApplication
from PyQt5.QtWebEngineWidgets import QWebEngineView
from PyQt5.QtCore import QUrl

class Browser(QWebEngineView):
    def __init__(self):
        super().__init__()
        self.loadProgress.connect(print)
        self.load(QUrl('https://google.com'))
        self.loadFinished.connect(self.pageReady)

    def pageReady(self, success):
        if success:
            self.resize(640, 480)
            self.show()
        else:
            print('page failed to load')

if __name__ == '__main__':
    app = QApplication(sys.argv)
    browser = Browser()
    app.exec_()

Using self.loadProgress.connect(print), I verified that the page does reach 100% progress -- but the browser window never appears. My firewall is disabled, so there shouldn't be a connection problem.

I'm on Windows 7, using PyQt5 (5.12.1), PyQt5-sip (4.19.15), and PyQtWebEngine (5.12.1). I installed them by running:
pip install pyqt5
pip install PyQtWebEngine
I did not install Qt separately.
I also tried PyQt5 5.12 without success.

[jsulm]

@freethewall Did you verify that pageReady is called?

[freethewall]

Yes, it is called, with success=True.