MODx.grid.Grid Sorting question

storeAddresses.grid.Items = function(config) {
    config = config || {};
    Ext.applyIf(config,{
        id: 'storeaddresses-grid-items'
        ,url: storeAddresses.config.connector_url
        ,baseParams: {
            action: 'mgr/item/getlist'
        }
        ,fields: ['id','city','street']
        ,autoHeight: true
        ,paging: true
        ,remoteSort: true
        ,columns: [{
            header: _('id')
            ,dataIndex: 'id'
			,sortable: true
            ,width: 70
        },{
            header: _('storeaddresses.city')
            ,dataIndex: 'city'
			,sortable: true
            ,width: 200
        },{
            header: _('storeaddresses.street')
            ,dataIndex: 'street'
			,sortable: false
            ,width: 250
        }]
        ,tbar: [{
            text: _('storeaddresses.item_create')
            ,handler: this.createItem
            ,scope: this
        }]
    });
    storeAddresses.grid.Items.superclass.constructor.call(this,config);
};
Ext.extend(storeAddresses.grid.Items,MODx.grid.Grid,{
    windows: {}

    ,getMenu: function() {
        var m = [];
        m.push({
            text: _('storeaddresses.item_update')
            ,handler: this.updateItem
        });
        m.push('-');
        m.push({
            text: _('storeaddresses.item_remove')
            ,handler: this.removeItem
        });
        this.addContextMenuItem(m);
    }
    
    ,createItem: function(btn,e) {
        if (!this.windows.createItem) {
            this.windows.createItem = MODx.load({
                xtype: 'storeaddresses-window-item-create'
                ,listeners: {
                    'success': {fn:function() { this.refresh(); },scope:this}
                }
            });
        }
        this.windows.createItem.fp.getForm().reset();
        this.windows.createItem.show(e.target);
    }
    ,updateItem: function(btn,e) {
        if (!this.menu.record || !this.menu.record.id) return false;
        var r = this.menu.record;

        if (!this.windows.updateItem) {
            this.windows.updateItem = MODx.load({
                xtype: 'storeaddresses-window-item-update'
                ,record: r
                ,listeners: {
                    'success': {fn:function() { this.refresh(); },scope:this}
                }
            });
        }
        this.windows.updateItem.fp.getForm().reset();
        this.windows.updateItem.fp.getForm().setValues(r);
        this.windows.updateItem.show(e.target);
    }
    
    ,removeItem: function(btn,e) {
        if (!this.menu.record) return false;
        
        MODx.msg.confirm({
            title: _('storeaddresses.item_remove')
            ,text: _('storeaddresses.item_remove_confirm')
            ,url: this.config.url
            ,params: {
                action: 'mgr/item/remove'
                ,id: this.menu.record.id
            }
            ,listeners: {
                'success': {fn:function(r) { this.refresh(); },scope:this}
            }
        });
    }
});
Ext.reg('storeaddresses-grid-items',storeAddresses.grid.Items);




storeAddresses.window.CreateItem = function(config) {
    config = config || {};
    this.ident = config.ident || 'mecitem'+Ext.id();
    Ext.applyIf(config,{
        title: _('storeaddresses.item_create')
        ,id: this.ident
        ,height: 150
        ,width: 475
        ,url: storeAddresses.config.connector_url
        ,action: 'mgr/item/create'
        ,fields: [{
            xtype: 'textfield'
            ,fieldLabel: _('name')
            ,name: 'name'
            ,id: 'storeaddresses-'+this.ident+'-name'
            ,width: 300
        },{
            xtype: 'textarea'
            ,fieldLabel: _('description')
            ,name: 'description'
            ,id: 'storeaddresses-'+this.ident+'-description'
            ,width: 300
        }]
    });
    storeAddresses.window.CreateItem.superclass.constructor.call(this,config);
};
Ext.extend(storeAddresses.window.CreateItem,MODx.Window);
Ext.reg('storeaddresses-window-item-create',storeAddresses.window.CreateItem);


storeAddresses.window.UpdateItem = function(config) {
    config = config || {};
    this.ident = config.ident || 'meuitem'+Ext.id();
    Ext.applyIf(config,{
        title: _('storeaddresses.item_update')
        ,id: this.ident
        ,height: 150
        ,width: 475
        ,url: storeAddresses.config.connector_url
        ,action: 'mgr/item/update'
        ,fields: [{
            xtype: 'hidden'
            ,name: 'id'
            ,id: 'storeaddresses-'+this.ident+'-id'
        },{
            xtype: 'textfield'
            ,fieldLabel: _('name')
            ,name: 'name'
            ,id: 'storeaddresses-'+this.ident+'-name'
            ,width: 300
        },{
            xtype: 'textarea'
            ,fieldLabel: _('description')
            ,name: 'description'
            ,id: 'storeaddresses-'+this.ident+'-description'
            ,width: 300
        }]
    });
    storeAddresses.window.UpdateItem.superclass.constructor.call(this,config);
};
Ext.extend(storeAddresses.window.UpdateItem,MODx.Window);
Ext.reg('storeaddresses-window-item-update',storeAddresses.window.UpdateItem);

$isLimit = !empty($_REQUEST['limit']);
$start = $modx->getOption('start',$_REQUEST,0);
$limit = $modx->getOption('limit',$_REQUEST,20);
$sort = $modx->getOption('sort',$_REQUEST,'id');
$dir = $modx->getOption('dir',$_REQUEST,'ASC');

$c = $modx->newQuery('Address');
$count = $modx->getCount('Address',$c);

$c->sortby($sort,$dir);
if ($isLimit) $c->limit($limit,$start);
$items = $modx->getCollection('Address',$c);

$list = array();
foreach ($items as $item) {
    $itemArray = $item->toArray();
    $list[]= $itemArray;
}

return $this->outputArray($list,$count);