Using QTimer.SingleShot to Report Minimizedness Gets the State Wrong

johnzhou721

See the following snippet.

import sys
from PySide6.QtWidgets import QApplication, QWidget
from PySide6.QtCore import Qt, QTimer
 
def monitor_and_report(window):
    state = window.windowState()
    is_min = window.isMinimized()
    flag_min = bool(state & Qt.WindowMinimized)
    print("window.isMinimized():", is_min)
    print("windowState has Qt.WindowMinimized flag:", flag_min)
 
def main():
    app = QApplication(sys.argv)
 
    window = QWidget()
    window.setWindowTitle("Minimized Window + Qt event loop")
    window.resize(400, 200)
    window.showMinimized()
    monitor_and_report(window)
 
    QTimer.singleShot(1500, lambda: monitor_and_report(window))
 
    sys.exit(app.exec())
 
if __name__ == "__main__":
    main()

The system already displays the window as minimized after I call the showMinimized function, and immediately reporting the state works correctly; however, if I wait a few seconds and then do it, it somehow actually gets the state wrong? What is this because of? Thanks!

jeremy_k

Which operating system and Qt release are being used?

I am not seeing this with macOS 15 and Qt 6.8.3 using an equivalent C++ program:

#include <QApplication>
#include <QWidget>
#include <QDebug>
#include <QTimer>

void monitor_and_report(QWidget *window)
{
    qDebug() << "window.isMinimized():" <<  window->isMinimized()
             << "windowState has Qt.WindowMinimized flag:"
             << (window->windowState() & Qt::WindowState::WindowMinimized);
}

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QWidget w;
    w.showMinimized();
    monitor_and_report(&w);
    QTimer::singleShot(1500, [&w]{ monitor_and_report(&w); });
    return a.exec();
}

Output:

window.isMinimized(): true
windowState has Qt.WindowMinimized flag: QFlags<Qt::WindowState>(WindowMinimized)
window.isMinimized(): true
windowState has Qt.WindowMinimized flag: QFlags<Qt::WindowState>(WindowMinimized)

You could try monitoring the QWindow::windowStateChanged() signal or WindowStateChange event.

johnzhou721

@jeremy_k

I installed PySide6 through pip. Version: plasmashell 6.3.4

Fedora KDE spin 42.

Also somehow compiling the program on fedora does not seem to give me any printing.

EDIT Hmm... seems like a Qt bug, it works on my macOS as well.

Any tips? Thanks

jeremy_k

@johnzhou721 said in Using QTimer.SingleShot to Report Minimizedness Gets the State Wrong:

@jeremy_k

I installed PySide6 through pip. Version: plasmashell 6.3.4

Fedora KDE spin 42.

I'm presuming that plasmashell is the KDE shell, which may not have anything to do with the Qt version. pypi.org doesn't list a corresponding package via the web search interface. Qt 6.3 was released in 2022. Fedora 42 was released in 2025. I would try upgrading to a more recent Qt release.

Getting the Qt version from PySide:

#!/usr/bin/env python3
from PySide6.QtCore import qVersion
print(qVersion())

Also somehow compiling the program on fedora does not seem to give me any printing.

Does compiling refer to invoking a C++ or other language compiler, or running the resulting program? Printing as in writing text to the console? What does the code look like?

EDIT Hmm... seems like a Qt bug, it works on my macOS as well.

It could be. It could be intentional windowing system behavior. I can only speculate without code.

SGaist

Hi,

Are you running wayland as window manager ?

johnzhou721

@jeremy_k I have 6.9.1 using your test script. Sorry about all this vagueness.

@SGaist echo $XDG_SESSION_TYPE gives wayland.

Thanks!

SGaist

Would it be possible to try it under Xorg to see if you have a different behavior ?

johnzhou721

@SGaist Unfortunately installing the xorg backend seems to get my login screen frozen (except cursor) on logout... since I had to force a shutdown from my VM and something bad happened I ended up reinstalling, and I don't want to deal with this again... there's advice telling me to use plasma-workspace-x11-6.0.3-1.fc40.x86_64.rpm online to deal with this but then I use an ARM64 VM... how should I be delaing with this if testing on X11 is impossible?

SGaist

For the package, there's likely an ARM version available.

The thing is:

it might be a wayland issue
it might be a composer issue
it might be a Qt/KDE issue

johnzhou721

@SGaist Doesn't happen with X11. Thanks for investigating this.

SGaist

So it looks like a wayland specific issue.

I would check the bug report system to see if there is something related and if not, please open a new issue with a sample script (even better if you could provide the C++ equivalent but not mandatory).

johnzhou721

Thanks for the advice!! In case anyone wants to look at the ticket here it is:

https://bugreports.qt.io/browse/QTBUG-139410