Flickering of webengineview when showing webGL content AND having an secondary screen attached

[raphm01]

I implement an application based on pyqt6 with a webengine view which shows a web page with webgl content. I noticed that a quite weird bug:
When I connect a secondary screen to the laptop, and only then, in an unpredictable fashion, the webengineview content starts and stops to flicker.

OS: Windows 11
pyqt version: 6.6.1
pyqt6-webengine: 6.6.0

Hardware:

• Lenovo Ideapad 330 with secondary screen attached (important!)
• CPU: Intel i5 8250U
• GPU: Intel UHD Graphics 620

Example code:

#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
WebGL Windows Flickering example, stripped down from original application

Hardware:
* Lenovo Ideapad 330 with secondary screen attached (important!)
* CPU: Intel i5 8250U
* GPU: Intel UHD Graphics 620
"""

import sys

from PyQt6.QtCore import QUrl
from PyQt6.QtWebEngineWidgets import QWebEngineView
from PyQt6.QtWidgets import QApplication, QMainWindow, QWidget, QVBoxLayout


class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()

        wgt_main = QWidget()
        self.layout_main = QVBoxLayout()
        wgt_main.setLayout(self.layout_main)
        self.setCentralWidget(wgt_main)

        self.wbv_main = QWebEngineView()
        self.wbv_main.load(QUrl("https://threejs.org/examples/#webgl_animation_keyframes"))
        self.wbv_main.show()

        self.layout_main.addWidget(self.wbv_main)
        self.showMaximized()


if __name__ == "__main__":
    # Start QT app
    app = QApplication(sys.argv)

    window = MainWindow()
    window.show()
    app.exec()

If I open the same web page with Chrome, I do not get any flickering at all.
The bug does not show up on Ubuntu or if no secondary screen is attached.

Can anybody make sense of this?

[raphm01]

Anybody?
I know that the bug is quite specific, but it is a showstopper, still since the environment described is very common (windows laptop with external screen)

[Dao Fa Nature]

self.showMaximized()Put it in front，
Because the initial window is small, flickering is when the window suddenly maximizes
from PyQt6.QtCore import QUrl
from PyQt6.QtWebEngineWidgets import QWebEngineView
from PyQt6.QtWidgets import QApplication, QMainWindow, QWidget, QVBoxLayout

class MainWindow(QMainWindow):
def init(self):
super().init()
self.showMaximized()
wgt_main = QWidget()
self.layout_main = QVBoxLayout()
wgt_main.setLayout(self.layout_main)
self.setCentralWidget(wgt_main)

    self.wbv_main = QWebEngineView()
    self.wbv_main.load(QUrl("https://threejs.org/examples/#webgl_animation_keyframes"))
    self.wbv_main.show()

    self.layout_main.addWidget(self.wbv_main)

if name == "main":
# Start QT app
app = QApplication(sys.argv)

window = MainWindow()
window.show()
app.exec()

[antony_qt]

Hello, @raphm01 Doyou resolve your problem? I have similar issue with terrible flickering of Webpage when using PyQT6 on windows OS