How can I sort options in an exposed views filter alphabetically? I am using an exposed Views Selective Filter which limits the options available quite nicely. However the display order of the Options is what is causing me the trouble. Here is an example of my Select list:

Accomodation
 - Camp Sites 
 - Hotels 
 - Rural Hotels

Beauty
 - Hair and Nails
 - Makeup
 - Spa

In the results these display exactly as I want them which is grouped by the Parent term (Accomodation, Beauty etc...). The trouble is that when I use the Views Selective Filter to only show options with results the list of options shows like this:


Camp Sites 
Hotels
Rural Hotel
Hair and Nails
Makeup
Spa


What I really want to do is to resort that list alphabetically before it is displayed to the User. I guess Hook Form Alter is the way to go but I can find anything anywhere on how to create the alpha sort option. I hope that all makes sense.
Thanks
j.Rowny's answer doesn't work because $form_state is not passed by reference.  You must actually modify the $form variable.  This worked for me:  

function yourcustommodule_form_views_exposed_form_alter(&amp;$form, $form_state) {
    foreach($form_state['view']-&gt;filter as $filter) {
        if($fid = $filter-&gt;options['expose']['identifier']) asort($form[$fid]['#options']);
    }
}