An important note for anyone using this module and having more than 1 Multiselect in a form make sure in the attributes array you set 'id' => 'unique_id' like this:

$form['name'] = array(
'#type' => 'fapi_multiselect',
'#attributes' => array('id' => 'unique_id'),
'#title' => t('Title'),
'#options' => array('Option 1', 'Option 2'),
);

Otherwise they all populate with the same information. I suggest the developer of this module add this to the example of the overview page.

Thanks
James.