$form empty inside options_validate()

$form is empty inside options_validate($form, &$form_state) making it impossible to set error messages.

function options_validate($form, &$form_state) {  
  dpm($form);

  parent::options_validate($form, $form_state);
  $options = &$form_state['values']['style_options'];

  if (!is_numeric($options['max_width'])) {
    form_error($form['max_width'], t('Please specify a numerical value for Max Width'));
  }
  if (!is_numeric($options['min_width'])) {
      form_error($form['min_width'], t('Please specify a numerical value for Min Width'));
  }
  if (!is_numeric($options['animate_in'])) {
      form_error($form['animate_in'], t('Please specify a numerical value for Animate In'));
  }
  if (!is_numeric($options['animate_out'])) {
    form_error($form['animate_out'], t('Please specify a numerical value for Animate Out'));
  }
  if (!is_numeric($options['activated_item'])) {
    form_error($form['activated_item'], t('Please specify a numerical value for Activated Item'));
  }
}

}