[QGIS-Developer] Qt and QGIS dialog's and Windows 11? Mine is disappearing?

[Richard Duivenvoorde]

Hi,

I'm developing a plugin with a rather huge (independent) dialog, so thought: let's make it popup modal in front of QGIS:

self.main_dlg.setModal(True)
# https://doc.qt.io/qt-5/qt.html#WindowModality-enum
self.main_dlg.setWindowModality(Qt.ApplicationModal)

All fine in my tests on Gnome and Windows 10

But then my colleague with a fresh Windows 11 laptop wanted to test... and as soon as he tried to resize the (large) dialog, it vanished and we could not bring it back anymore (other then restarting the plugin).
So at first it looks fine, it is modal, you can click next to it without issue, but as soon as you touch the dialog borders to resize: gone.
And it's really gone, not as if it moved behind the QGIS dialog or so (which I had with other plugins), really vanished (and keeping QGIS modal/unresponsive sometimes)... Also it is not visible as a 'second dialog' or so in the task bar...

Others have seen this?
Or have pointers?

Else I will try to create an issue with a minimal plugin to be able to demonstrate it (or make it reproducable by others with Windows 11 (which I myself do not have running anywhere yet)).

Regards,

Richard Duivenvoorde