Error classes are not applied to "checkboxes" or "radios"

Does this issue exist in current D6?

Patch works. I can confirm this bug. Implications are deep and I've wasted couple of hours because of this bug. Finally I've made exactly the same patch. It is pity that I didn't find this issue earlier. I am using Vertical Tabs and this bug causes me big problem with tabs, which should be activated when some of their elements didn't pass validation. Look at #1108574: "required indicator" dont show when CCK-TextField is "Checkboxes/radio buttons"? Class 'error' should be added to checkboxes and radios element too since property #required is set for this elements. Look at function optionwidgets_buttons_process inside optionwidgets module: http://drupalcontrib.org/api/drupal/contributions--cck--modules--optionw... Property #required is set for checkboxes. It is obvious, that element checkboxes should be selected as invalid (with class 'error') when validation fails. Without this patch we have inconsistent behavior and other modules (like Vertical Tabs) has no chance to work properly.

drupal-6-3-form-error-classes-v1.patch queued for re-testing.

One notice. If you don't want to patch the core you could use theme functions inside template.php of YOUR_THEME

function YOUR_THEME_checkboxes($element) {
  _form_set_class($element, array('form-checkboxes'));
  $element['#children'] = '<div '. drupal_attributes($element['#attributes']) .'">'. (!empty($element['#children']) ? $element['#children'] : '') .'</div>';
  if ($element['#title'] || $element['#description']) {
    unset($element['#id']);
    return theme('form_element', $element, $element['#children']);
  }
  else {
    return $element['#children'];
  }
}

function YOUR_THEME_radios($element) {
  _form_set_class($element, array('form-radios'));
  $element['#children'] = '<div '. drupal_attributes($element['#attributes']) .'">'. (!empty($element['#children']) ? $element['#children'] : '') .'</div>';
  if ($element['#title'] || $element['#description']) {
    unset($element['#id']);
    return theme('form_element', $element, $element['#children']);
  }
  else {
    return $element['#children'];
  }
}

This would be the patch for D7. But it also needs theming changes so I wouldn't applied it as is. system.messages.css which contains this line:

div.error {
  background-image: url(../../misc/message-24-error.png);
  border-color: #ed541d;
}
<code>

The diff is as follows:

<code>
--- a/includes/form.inc
+++ b/includes/form.inc
@@ -2822,7 +2822,7 @@ function theme_radios($variables) {
   if (isset($element['#id'])) {
     $attributes['id'] = $element['#id'];
   }
-  $attributes['class'] = 'form-radios';
+  _form_set_class($element, array('form-radios'));
   if (!empty($element['#attributes']['class'])) {
     $attributes['class'] .= ' ' . implode(' ', $element['#attributes']['class']);
   }

Also, this seems to be a duplicate of #222380: No error highlighting on form checkbox or radio input types. So I think this should be closed instead anyway =P.