Child QQuickWidget doesn't handle geometry change (e.g. when moving widgets in a layout)

#include <QQuickWidget>
#include <QtWidgets>

class HideShow : public QObject {
    Q_OBJECT
public:

    QWidget *subject;
    HideShow(QWidget *subject, int interval) : QObject(subject), subject(subject)
    {
        startTimer(interval);
    }

    void timerEvent(QTimerEvent *)
    {
        if (subject->isVisible()) {
            subject->hide();
        } else {
            subject->show();
        }
    }
};

int main(int argc, char **argv)
{
    QApplication app(argc, argv);
    QWidget *toplevel = new QWidget;

    QVBoxLayout *groupLayout = new QVBoxLayout;
    QUrl source("qrc:quickwidget/rotatingsquare.qml");

    QQuickWidget *above = new QQuickWidget;
    above->setResizeMode(QQuickWidget::SizeRootObjectToView);
    above->setSource(source);
    above->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
    above->setFixedHeight(50);
    groupLayout->addWidget(above);

    QQuickWidget *w = new QQuickWidget;
    w->setResizeMode(QQuickWidget::SizeRootObjectToView);
    w->setSource(source);
    w->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
    groupLayout->addWidget(w);

    QQuickWidget *below = new QQuickWidget;
    below->setResizeMode(QQuickWidget::SizeRootObjectToView);
    below->setSource(source);
    below->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
    below->setFixedHeight(50);
    groupLayout->addWidget(below);

    new HideShow(w, 3000);
    toplevel->setMinimumHeight(170);
    toplevel->setLayout(groupLayout);
    toplevel->show();
    return app.exec();
}

#include "main.moc"

#include <QQuickWidget>
#include <QtWidgets>

class HideShow : public QObject {
    Q_OBJECT
public:

    QWidget *subject;
    HideShow(QWidget *subject, int interval) : QObject(subject), subject(subject)
    {
        startTimer(interval);
    }

    void timerEvent(QTimerEvent *)
    {
        if (subject->isVisible()) {
            subject->hide();
        } else {
            subject->show();
        }
    }
};

int main(int argc, char **argv)
{
    QApplication app(argc, argv);
    QWidget *toplevel = new QWidget;

    QVBoxLayout *groupLayout = new QVBoxLayout;

    QLCDNumber *above = new QLCDNumber;
    above->display(1337);
    above->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
    above->setFixedHeight(50);
    groupLayout->addWidget(above);

    QLCDNumber *w = new QLCDNumber;
    w->display(1338);
    w->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
    groupLayout->addWidget(w);

    QLCDNumber *below = new QLCDNumber;
    below->display(1339);
    below->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
    below->setFixedHeight(50);
    groupLayout->addWidget(below);

    new HideShow(w, 3000);
    toplevel->setMinimumHeight(170);
    toplevel->setLayout(groupLayout);
    toplevel->show();
    return app.exec();
}

#include "main.moc"