When reshowing a hidden subwindow, Qt Wayland Compositor will issue a protocol error and crash the client. This does not happen with e.g. mutter

Create a simple Qt Widgets template app, add a QDialog *w member, then add a button to it and connect it to the following slot:

void MainWindow::toggleSubWindow()
{
    if (w == nullptr)
        w = new QDialog(this);

    if (w->isVisible())
        w->hide();
    else
        w->show();
}

Clicking the button three times crashes the app. This is likely triggered by https://codereview.qt-project.org/c/qt/qtwayland/+/583059