Using GridView.SnapToRow and GridView.ApplyRange with a top margin leads to view jumps

import QtQuick 2.0

GridView {
    id: gridView
    width: 400; height: 400
    cellHeight: height/ 3
    cellWidth: width / 5
    model: 30

    topMargin: 50
    snapMode: GridView.SnapToRow
    preferredHighlightBegin: 50
    preferredHighlightEnd: 50
    highlightRangeMode: GridView.ApplyRange

    delegate: Rectangle {
        width: gridView.cellWidth
        height: gridView.cellHeight
        color: index % 3 == 0 ? "#00FF00" : index % 2 == 0 ? "#FFFF00" : "#0000FF"
    }

    highlight: Rectangle { color: "red"; z: 2 }
    highlightMoveDuration: 1000

    Rectangle {
        id: scrollbar
        y: gridView.visibleArea.yPosition * gridView.height
        width: 10
        height: gridView.visibleArea.heightRatio * gridView.height
        color: "black"
    }

    Rectangle {
        width: 50; height: 50
        color: "black"
        anchors.right: parent.right
        anchors.bottom: parent.bottom

        MouseArea {
            anchors.fill: parent
            onClicked: gridView.currentIndex = gridView.currentIndex + 5
        }
    }
}