Changing the height of a positioner in a ListView causes the view to jump

import QtQuick 2.0

ListView {
    id: root

    property real panelSize: 200

    width: 200; height: 200

    model: VisualItemModel {
        Column {
            id: first
            objectName: "column"
            Repeater {
                id: rpt
                model: 1
                Rectangle {
                    width: 80; height: 80; color: "red"; border.width: 1
                    Text { text: first.x + ", " + first.y }
                }
            }
        }
        Rectangle {
            objectName: "yellow"
            width: root.panelSize; height: root.panelSize; color: "yellow"
            Text { text: parent.x + ", " + parent.y }
        }
        Rectangle {
            objectName: "blue"
            width: root.panelSize; height: root.panelSize; color: "blue"
            Text { text: parent.x + ", " + parent.y }
        }
    }

    focus: true
    highlightMoveDuration: 2000

    Keys.onSpacePressed: {
        rpt.model += 1
    }

    Keys.onDigit1Pressed: currentIndex = 0
    Keys.onDigit2Pressed: currentIndex = 1
    Keys.onDigit3Pressed: currentIndex = 2
}