Chained Selectfields -- Sencha Touch 2.0 - select

Question

I am using the Sencha Touch 2.0 KitchenSink example to try to learn some of the basics. I am getting stuck on chained selectfields though.
I am going off the tutorial here but with the different setup I am being thrown off. The code below runs perfectly in the Forms.js file in kitchensink, but I am missing on the actual chainedselect part of it.
EDIT: What I am asking is how to make chained selectfields. I have the datastores and the selectfields in the example code, but not a working chained selectfield from first to second.
Ext.regModel('First', {
idProperty: 'FirstID',
fields: [{
name: 'FirstID',
type: 'int'
}, {
name: 'FirstName',
type: 'string'
}]
});
Ext.regModel('Second', {
idProperty: 'SecondID',
fields: [{
name: 'SecondID',
type: 'int'
},{
name: 'FirstID',
type: 'int'
}, {
name: 'SecondName',
type: 'string'
}]
});
var firstStore = new Ext.data.Store({
model: 'First',
data: [{
FirstID: 1,
FirstName: 'Kenworth'
}, {
FirstID: 2,
FirstName: 'Peterbilt'
}],
autoLoad: true
});
var secondStore = new Ext.data.Store({
model: 'First',
data: [{
SecondID: 1,
FirstID: 1,
SecondName: 'T800'
}, {
SecondID: 2,
FirstID: 1,
SecondName: 'T700'
}, {
SecondID: 3,
FirstID: 1,
SecondName: 'T660'
}, {
SecondID: 4,
FirstID: 1,
SecondName: 'T470'
}],
autoLoad: true
});
Ext.define('Kitchensink.view.Forms', {
extend: 'Ext.tab.Panel',
requires: [
'Ext.form.Panel',
'Ext.form.FieldSet',
'Ext.field.Number',
'Ext.field.Spinner',
'Ext.field.DatePicker',
'Ext.field.Select',
'Ext.field.Hidden'
],
config: {
activeItem: 0,
tabBar: {
// docked: 'bottom',
ui: 'dark',
layout: {
pack: 'center'
}
},
items: [
{
title: 'Basic',
xtype: 'formpanel',
id: 'basicform',
iconCls: 'refresh',
items: [
{
xtype: 'fieldset',
title: 'Enter Data',
instructions: 'Please enter the information above.',
defaults: {
labelWidth: '35%'
},
items: [
{
xtype: 'selectfield',
name: 'firstfield',
label: 'First',
store: firstStore,
displayField: 'FirstName',
valueField: 'FirstID'
}, {
xtype: 'selectfield',
name: 'secondfield',
label: 'Second',
store: secondStore,
displayField: 'SecondName',
valueField: 'SecondID'
}
]
}
]
}
]
},
onFirstChange: function(selectField, value){
var secondSelectField = this.items.get(1);
secondSelectField.store.clearFilter(); // remove the previous filter
// Apply the selected Country's ID as the new Filter
secondSelectField.store.filter('FirstID', value);
// Select the first City in the List if there is one, otherwise set the value to an empty string
var firstValue = secondSelectField.store.getAt(0);
if(firstValue){
secondSelectField.setValue(firstValue.data.SecondID);
} else {
secondSelectField.setValue('');
}
}
});