Mouse position events can't be passed through nested MouseArea

import QtQuick 2.2
import QtQuick.Controls 1.1

Rectangle {
    color: "red"
    width: 100
    height: 100
    
    MouseArea {
        id: outer
        anchors.fill: parent
        hoverEnabled: true
    }

    Label { text: outer.mouseX + "," + outer.mouseY }

    Rectangle {
        color: "blue"
        width: 50
        height: 50
        anchors.centerIn: parent
        
        MouseArea {
            id: inner
            anchors.fill: parent
            hoverEnabled: true

            onPositionChanged: {
                mouse.accepted = false // documentation says this is ignored, why is that?
            }
        }

        Label { text: inner.mouseX + "," + inner.mouseY }
    }
}