ComboBox send warning message when model is set to 0 &

QtQuick ComboBox show

ComboBox.qml:339:35: Unable to assign null to QString

When its pointed to a QSqlQueryModel it shows following error message

ComboBox.qml:470: TypeError: Cannot read property 'constructor' of undefined

Sample code

import QtQuick 2.1
import QtQuick.Controls 1.0

ApplicationWindow {
    width: 640
    height: 480
    ComboBox {
        anchors.centerIn: parent
        model: 0
    }
}