checkboxgroup setValue does not work with a string of names

[raj_plays]

Hi,
I have a checkboxgroup with checkboxes defined as

id: 'daysCheckboxGroup',
xtype: 'checkboxgroup',
fieldLabel: 'Select Days',
columns: 4,
items: [
{
    name: 'day_1',
    inputValue: 1,
    boxLabel: 'Mon'
}, {
    name: 'day_2',
    inputValue: 2,
    boxLabel: 'Tue'
} {
    name: 'day_3',
    inputValue: 3,
    boxLabel: 'Wed'
}]

After the checkbox group is rendered, if I do
Ext.getCmp('daysCheckboxGroup').setValue('day_1,day_2');
it does not work but according to the API docs it should.
Passing an array of booleans to setValue works but I want to pass a string of names.

[mitchellsimoens]

What version of Ext JS 4.x.x are you using? We could not reproduce this.

[raj_plays]

Its ver. 3.3.1.
All other overloaded versions of setValue() work but not this one.