diff --git includes/form.inc includes/form.inc
index b639fa6..a6a24fe 100644
--- includes/form.inc
+++ includes/form.inc
@@ -2622,8 +2622,15 @@ function form_get_options($element, $key) {
  * @param $variables
  *   An associative array containing:
  *   - element: An associative array containing the properties of the element.
- *     Properties used: #attributes, #children, #collapsed, #collapsible,
- *     #description, #id, #title, #value.
+ *     Properties used:
+ *     - "#attributes": An array of HTML attributes of the fieldset tag. (Required)
+ *     - "#children": Preprocessed HTML body of the fieldset. (Required)
+ *     - "#collapsed": Whether the fieldset is initially collapsed. Defaults to FALSE.
+ *     - "#collapsible": Whether the fieldset may be collapsed.  Defaults to FALSE.
+ *     - "#description": An optional description to insert at the top of the fieldset.
+ *     - "#id": An optional ID attribute for the fieldset tag.
+ *     - "#title": An optional title to be wrapped in a legend tag.
+ *     - "#value": An optional text string to insert at the bottom of the fieldset.
  *
  * @ingroup themeable
  */