frameless windows with qt5 (qml)

I spent some good hours on web searching but nothing help me..

I build GUI with QML and I want him without frame.

I tried to change my main.cpp like this:

#include <QtGui/QGuiApplication>
#include "qtquick2applicationviewer.h"

int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);
    QtQuick2ApplicationViewer viewer;

    viewer.setMainQmlFile(QStringLiteral("qml/RR_QML/main.qml"));
    viewer.setFlags(Qt::FramelessWindowHint | Qt::Window);
    viewer.showExpanded();

    return app.exec();
}

I also tried to change main.qml file:

Window
{
    id: rootWindow
    flags: Qt.FramelessWindowHint | Qt.Window

    // my qml code here
}

but nothing work.

I'll glad for any help, thanks!

I work with:

• Win 7 x64
• Qt 5.1.1