Hello,

I'm trying to add custom classes to my form elements, however I keep getting "Sorry, there was a problem with handling your request.". I don't quite understand what I'm doing wrong, according to API's what I have is correct.

$form = new Form($this, 'GameResultForm', $fields, $actions, $requiredFields);
        $form->dataFieldByName('RiotGameID')->addExtraClass('required');
        return $form;

my php error logs are not logging anything

$form->Fields()->dataFieldByName('RiotGameID')->addExtraClass('required');
// or
$fields->dataFieldByName('RiotGameID')->addExtraClass('required');

http://doc.silverstripe.org/en/developer_guides/forms/introduction/

PS: You need to set the site's environment to 'dev' mode to get proper error notices.

That worked, thank you!