qt.qpa.wayland: wrong transient parent of the popup

qt.qpa.wayland: Creating a popup with a parent, QWidgetWindow(0x55613181efd0, name="QMainWindowClassWindow") which does not match the current topmost grabbing popup, QWidgetWindow(0x5561325ddca0, name="QMenuClassWindow") With some shell surface protocols, this is not allowed. The wayland QPA plugin is currently handling it by setting the parent to the topmost grabbing popup. Note, however, that this may cause positioning errors and popups closing unxpectedly. Please fix the transient parent of the popup.

/*
 *  SPDX-FileCopyrightText: 2025 Christoph Cullmann <cullmann@kde.org>
 *
 *  SPDX-License-Identifier: MIT
 */

#include <QApplication>
#include <QMainWindow>
#include <QMenu>
#include <QMenuBar>
#include <QAction>

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QMainWindow test;

    auto m = new QMenuBar(&test);
    test.setMenuBar(m);

    auto s = m->addMenu(QStringLiteral("testm"));
    auto s2 = m->addMenu(QStringLiteral("testm2"));

    QAction *a = new QAction(QStringLiteral("test"), &test);
    s->addAction(a);
    s2->addAction(a);
    a->setMenu(new QMenu());

    a->menu()->addAction(QStringLiteral("test"));

    test.show();

    return app.exec();
}