Qml Button Tooltips not working in QQuickView

import QtQuick 2.1
import QtQuick.Controls 1.0

Rectangle {
    Button {
        text: "Hello World"
        tooltip: "testing this functionality"
    }
}

#include <QtGui/QGuiApplication>

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

    QQuickView view;
    view.setSource(QUrl("qml/main.qml"));
    view.show();
    return app.exec();
}