Creating a basic select box in ExtJS

I'm currently working on a project that involves generating an entirely ExtJS-based interface from PHP code.

I needed to be able to produce in ExtJS the equivelent of a standard HTML <select> box. This can be achieved with a ComboBox, however, it seems that ComboBoxes are heavily geared towards doing lots of clever things like loading in options over AJAX, allowing the user to type in their own options, auto-completing typed in options, etc. That's all great but if all you want is a standard drop-down with a predefined set of options it takes a bit of work.

I incorrectly assumed that something like the following would work:

obj_combo = new Ext.form.ComboBox({
 name: 'countries',
 items: [
  {value: '1', text: 'UK'},
  {value: '2', text: 'US'},
// ...
]
});

Unfortunaltey, it's not that simple.

Here's an example of the actual code required:

obj_combo = new Ext.form.ComboBox({
 name: 'countries',
// Stop users being able to type in the combobox
 editable: false,
// Even though the user cant type any more
// once they select one option it'll remove any
// others that don't start with the same letters
// unless we turn off filtering
 disableKeyFilter: true,
// Only allow users to pick an option that exists
// in the list of options (not one of their own)
 forceSelection: true,
// This isn't entirely necessary but the combox
// will start off blank otherwise
 emptyText: '--select one--',
// This one's vital: when the user clicks on the
// drop-down show ALL options
 triggerAction: 'all',
// By default it retrieves remote data,
// we're using local data
 mode: 'local',
// ComboBox will only accept data from a Store
// so we have to create a basic one
 store: new Ext.data.SimpleStore({
  id: 0,
  fields: ['value', 'text'],
  data : [['1', 'UK'], ['2', 'US']]
 }),
// Specify which fields in the store hold
// the value and the display text
 valueField: 'value',
 displayField: 'text',
// Important: by default the POST/GET data
// for this item will contain the display text
// not the value. This option creates a hidden field
// with the same name as the dropdown containing the
// selected value so it is that which gets returned
 hiddenName: 'countries'
});

With all those set (plus any of your own) you should have the equivalent of an HTML select box in ExtJS.

For good examples of different ComboBoxes (but unfortunately little explanation of them) check this link:
http://extjs.com/deploy/ext/examples/form/combos.html