xcb: Synthesized mouse from touch gets stuck

I have witnessed the application failing to synthesize any mouse events after an arbitrary running time, this rendering the QApplication inoperable, as those machines have no physical mouse. After a restart of the application (which, also restarts X11), the mouse events return for a while; there seems to be no rhyme or reason what triggers this behaviour; sometimes, this does not happen for days, sometimes it can occur within minutes of application startup.

I couldn't reproduce it in gnome. In gnome you can't click quickly because there are effects.

For reproduce you can use xfce4 or openbox desktop except gnome.

it occurs if you open QDialog and remove layer.

Qt 5.13.2

https://www.veed.io/view/5210b05a-4d35-4788-9017-82dca381b9d2

Qt 5.15.2 - 6.3.1

https://www.veed.io/view/645f04ec-b389-4a43-97b2-a97eabf63685

i use python but i tried standard c++ version too same result.

I am sharing the python code. I just open a message box and when we close it quickly the touch starts to hang. It never works again until I restart the app, same for c++.

If I set the Qt::WA_DeleteOnClose flag to false and ı create a messagebox and change the message each time and display the object without killing it, this problem does not occur. But if the dialog is closed and deleted, this error starts to happen.

ı found similar bug https://bugreports.qt.io/browse/QTBUG-98519  but the bug still persists