[dev] With this prefs.php changes aren't saved. Any ideas?

[Robin Rainton]

Sorry, sorry - complete dumb newbie question but can't find anything in 
Wiki or archives about this:

For a new app, I've placed the following in config/prefs.php:

---snip---
$prefGroups['doesthismatter?'] = array(
    'column' => _("General Options"),
    'label' => _("Job Entry Options"),
    'desc' => _("Options affecting entry of jobs."),
    'members' => array('default_point_count')
);

$_prefs['default_point_count'] = array(
    'value' => '2',
    'locked' => false,
    'shared' => false,
    'type' => 'enum',
    'enum' => array('0' => _("None"),
                    '1' => "1",
                    '2' => "2",
                    '3' => "3",
                    '4' => "4",
                    '5' => "5"),
    'desc' => _("Number of points on a new job:")
);
---snip---

All the existing apps are having their prefs correctly stored. The prefs 
form on this new app is displayed correctly when pressing the 'Options' 
icon on the menu. However, when 'Save Options' is clicked the page 
simply refreshes. No DB update and no message stating they have been saved.

Again, I know this is probably trivial, but sure there's something very 
small I've missed, help much appreciated.

Thanks,

Robin