Dynamic creation of Emitter objects cause flickering

import QtQuick 2.5
import QtQuick.Window 2.2
import QtQuick.Particles 2.0

Window {
    visible: true
    width: 640
    height: 480

    Rectangle {
        id: particle
        width: 30
        height: width
        radius: width / 2
        color: "white"
        visible: false
        Component.onCompleted: {
            particle.grabToImage(function(result) {
                particleImage.source = result.url;
            })
        }
    }

    Rectangle {
        anchors.fill: parent
        color: "black"

        ParticleSystem {
            id: particleSystem
            anchors.fill: parent

            ImageParticle {
                id: particleImage
                width: 30; height: 30
            }
        }
    }

    MultiPointTouchArea {
        anchors.fill: parent
        onPressed: {
            for (var i = 0 ; i < touchPoints.length ; i++)
                emitterComponent.incubateObject(
                            particleSystem, {
                                x: touchPoints[i].x,
                                y: touchPoints[i].y
                            })
        }
    }

    Component {
        id: emitterComponent

        Emitter {
            emitRate: 10
            velocity: PointDirection {x: 0; y: 0; xVariation: 200; yVariation: 200;}
            size: 30
            Timer {
                running: true
                interval: 1000
                onTriggered: {
                    parent.destroy()
                }
            }
        }
    }
}