QQuickItem: cannot filter key events

#include <QtQuick>

class Filter : public QObject
{
    bool eventFilter(QObject* object, QEvent* event)
    {
        if (event->type() == QEvent::KeyPress || event->type() == QEvent::KeyRelease || event->type() == QEvent::ShortcutOverride) {
            // always a shortcut override (double)...?
            // QQuickItem(0x13d5810, name = "item") QKeyEvent(ShortcutOverride, 41, 0, ""a"", false, 1) 
            qDebug() << object << static_cast<QKeyEvent*>(event);
        }
        return false;
    }
};

int main(int argc, char* argv[])
{
    QGuiApplication app(argc, argv);
    Filter filter;
    QQmlApplicationEngine engine;
    engine.loadData("import QtQuick 2.1; import QtQuick.Window 2.1; Window { width: 360; height: 360; Item { anchors.fill: parent; objectName: 'item'; focus: true } }");
    QWindow* window = qobject_cast<QWindow*>(engine.rootObjects().value(0));
    if (window) {
        window->show();
        QObject* item = window->findChild<QObject*>("item");
        if (item)
            item->installEventFilter(&filter);
    }
    return app.exec();
}