Qml flicker on animation in frameless QQuickView

#include <QGuiApplication>
#include <QQuickView>

int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);
    QQuickView *view= new QQuickView;
    view->setFlags(Qt::FramelessWindowHint);
    view->show();
    view->setSource(QUrl(QStringLiteral("qrc:/main.qml")));
    return app.exec();
}

import QtQuick 2.0

Rectangle {
    width: 100
    height: 100
    color: "#80808080"

    Rectangle {
        width: 10
        height: 10
        anchors.centerIn: parent
        RotationAnimation on rotation {
            duration : 15000
            easing.type: Easing.Linear
            loops: Animation.Infinite
            from: 0
            to: 360
        }
    }
}