initialize error of ComboBox : Cannot read property 'constructor' of undefined

[stereoMatching]

When I try to initialize the model of ComboBox, weird error pop out

import QtQuick 2.2
import QtQuick.Controls 1.1
 
Rectangle {
    width: 100
    height: 62
 
    ListModel{
        id: modelA
    }
 
    ComboBox{
        model: modelA
    }
 
    Component.onCompleted: {
        modelA.append({"source" : "hhhh"})
    }
}

import QtQuick 2.2
import QtQuick.Controls 1.1

Rectangle {
    width: 100
    height: 62

    ListModel{
        id: modelA
    }

    ComboBox{
        model: modelA
    }

    Component.onCompleted: {
        modelA.append({"source" : "hhhh"})
    }
}

To copy to clipboard, switch view to plain text mode 

error message

file:///C:/Qt/Qt5.2.0/5.2.0/mingw48_32/qml/QtQuick/Controls/ComboBox.qml:496: TypeError: Cannot read property 'constructor' of undefined

How could I fix this error?

[stereoMatching]

Found the solution, use loader to load the ComboBox when insert or http://stackoverflow.com/questions/2...47640_20833809