GridPanel, try to 'multiselect' rows by code, but only the last is selected

[loginfabio]

Hello,

I have a gridpanel in a form with a CheckboxModel, when I load the store, I have a callback that find the requested records and selects the rows, but I found that only the last record is selected.
I try adding 'multiSelect: true, simpleSelect: true' in the grid configuration, but result doesn't change.

Here's some code

GRIDPANEL view:

Ext.define('Smqs.view.knowledgebase.KlbGroupGrid', {
    extend: 'Ext.grid.Panel',
    requires: ['Ext.selection.CheckboxModel'],
    alias: 'widget.smqs-klbgroupgrid',id:'klbgroupgrid',
    height: 154,
    multiSelect: true, simpleSelect: true,
    store:'Groups',
    viewConfig:{enableRowBody:true},
    initComponent: function(){
        var me = this,
        aColumns = [
                {text: 'NAME', width:'95%', dataIndex:'GRNO'}
            ],
        sm = Ext.create('Ext.selection.CheckboxModel', {mode : 'MULTI'});
        Ext.apply(this,{selModel: sm, columns: aColumns});
        this.callParent();
    }
}); 

WINDOW controller (init - show)

Ext.getStore('Groups').load({
    callback: function (records, operation, success) {
        var vire = val.down('form').down('#klbgroupgrid').getView();
        vire.select(0);
        vire.select(1);
        vire.select(2);
        //for (var i=0;i<nure;i++) {
        //    var rowIndex = this.find('GRID', parseInt(arre[i]));
        //    if (rowIndex>=0) {
        //        vire.select(rowIndex);
        //    }
        //}
    }
}); 

I've commented the loop and forced to select the first three rows and
only the 3rd row results selected.

Thanks in advance

[loginfabio]

Sorry...

I haven't read documentation completely, I've changed code to:

Ext.getStore('Groups').load({
    callback: function (records, operation, success) {
        var vire = val.down('form').down('#klbgroupgrid').getSelectionModel();
        vire.select(0,true);
        vire.select(1,true);
        vire.select(2,true);
        //for (var i=0;i<nure;i++) {
        //    var rowIndex = this.find('GRID', parseInt(arre[i]));
        //    if (rowIndex>=0) {
        //        vire.select(rowIndex);
        //    }
        //}
    }
}); 

and it works.