Using a ShaderEffectSource on a WebView results in incorrect rendering

 
import QtQuick 2.0
import QtWebKit 3.0

Rectangle {
    width: 600
    height: 600
    color: "black"
    Column {
        id: container
        anchors.fill: parent
        Rectangle {
            width: parent.width
            height: parent.height * (1/3)
            color: "gray"
        }
        WebView {
            width: parent.width
            height: parent.height * (2/3)
            url: "http://qt-project.org/"
        }
    }
    ShaderEffectSource {
        anchors.fill: container
        sourceItem: container
        hideSource: true
        live: true
    }
}