QQuickWidget breaks Tab focus chain

// Example.qml
import QtQuick 2.4

Rectangle {

    width: 50
    height: 50
    activeFocusOnTab: true
    color: activeFocus ? "green" : "red"

    Rectangle {
        anchors.fill: parent
        anchors.margins: 10
        focus: true
        activeFocusOnTab: true
        color: activeFocus ? "green" : "red"

        Rectangle {
            anchors.fill: parent
            anchors.margins: 10
            focus: true
            activeFocusOnTab: true
            color: activeFocus ? "green" : "red"
        }
    }
}

// main.cpp

#include <QApplication>
#include <QQuickWidget>
#include <QFrame>

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QQuickWidget w1(QUrl("qrc:/Example.qml"));
    QQuickWidget w2(QUrl("qrc:/Example.qml"));
    QFrame *frame = new QFrame();
    QVBoxLayout *layout = new QVBoxLayout(frame);
    layout->addWidget(&w1);

    // Try to uncomment the next line and see how the focus
    // behaviour changes.
    // layout->addWidget(&w2); 

    frame->show();
    return app.exec();
}