Ext version tested:

Ext 4.1.1(GA)


Browser versions tested against:
Chromium 18.0.1025.168 (Ubuntu 12.04)

Description:
The idProperty property invalid of reader.


Code:
Ext.define('App.store.ContactsList', {
extend: 'Ext.data.Store', 
fields: [
        { name: 'userid', type: 'int' },
        { name: 'ownerid', type: 'int'},
        { name: 'rname', type: 'string'},
        { name: 'call', type: 'string' },
        { name: 'email', type: 'string' },
        { name: 'online', type: 'int'},
        { name: 'sex', type: 'boolean' },
        { name: 'usertype', type: 'string'}
        ],
proxy: {
    type: 'rest',
    appendId: false,
    url: '/openService.ashx/contactlist',
    headers: { 'Accept': 'application/json' },
    writer: {
            type: 'json',
            allowSingle: true
            ,writeAllFields: true
        },
    reader: {
        type: 'json',
        root: 'data',
        idProperty: 'userid'
    },
    listeners: { exception:  proxyFailure
    }
}
});
var ctlStore=Ext.create('App.store.ContactsList',{autoLoad: true, autoSync: false});
Log(ctlStore.getCount()); // log: 3
ctlStore.each(function (record) {
Log(record.getId()); //No log
});