Help with ListModel and setProperty

[Mark81]

When I try to change a property value of an item contained into a ListModel the following code has no effect:

Main.qml

import QtQuick 2.0

Item {
    anchors.fill: parent

    ListModel { id: modelCrayon }

    Component.onCompleted: {
        for (var i = 0; i < 10; i++)
            modelCrayon.append( { _tag: i, _source: "resources/crayon-green.png", _selected: false } )
    }

    Column {
        x: -170
        spacing: 0
        Repeater {
            model: modelCrayon
            delegate: Crayon {
                tag: _tag
                source: _source
                selected: _selected
                onCrayonSelected: {
                    for (var i = 0; i < modelCrayon.count; i++) {
                        if (i == tag) continue;
                        modelCrayon.setProperty(i, "_selected", false);
                    }
                }
            }
        }
    }
}

Crayon.qml

import QtQuick 2.0

Image {
    property bool selected
    property int tag
    signal crayonSelected()

    id: crayon
    smooth: true
    fillMode: Image.PreserveAspectFit

    onSelectedChanged: console.debug(tag, selected)

    MouseArea {
        anchors.fill: parent
        onClicked: {
            selected = !selected
            if (selected) crayonSelected()
        }
    }

    states: State {
        name: "selected"; when: selected == true
        PropertyChanges { target: crayon; x: 30 }
    }

    transitions: Transition {
        from: ""; to: "selected"
        PropertyAnimation { property: "x"; duration: 500; easing.type: Easing.InOutQuad }
    }

}

Nothing is shown on console, so the "selected" var is never changed. I'm sure there's something obvious I'm missing.

By the way, is there a smarter way to use a ListModel as a OptionBox? I mean I want only ONE item at time must have the selected property == true. Or, in other words, keep tracks of the selected index.

[Mark81]

I wasn't able to fix the issue but I solved my problem using a ListView instead of a Column and setting the selected property as ListView.isCurrentItem in the delegate.