$form->isblank('created_for_user', $locale->text('You must chose a user.'));
$form->isblank('follow_up_date', $locale->text('The follow-up date is missing.'));
$form->isblank('subject', $locale->text('The subject is missing.'));
$form->isblank('created_for_user', $locale->text('You must chose a user.'));
$form->isblank('follow_up_date', $locale->text('The follow-up date is missing.'));
$form->isblank('subject', $locale->text('The subject is missing.'));