form_checkbox and set_checkbox

[eluser]froginvasion[/eluser]
It seems that didn't really fix my problem:
I used the array, but that really doesn't do anything different, so maybe I am missing something here:
I just group my checkboxes by name, and in my rules, it has one rule for this checkboxgroup:

Code:

array('field' => 'locatie','label' => 'Locaties','rules' => 'trim|required'),

So why does it only fill one of them up again, and don't tell me to fiddle with if/else statements to fix this,
that's just... not how it should be.