diff --git a/lib/questionlib.php b/lib/questionlib.php
index 6e605dbcac5..2c77edada31 100644
--- a/lib/questionlib.php
+++ b/lib/questionlib.php
@@ -484,7 +484,7 @@ function question_delete_course_category($category, $newcategory, $feedback=true
 /**
  * Enter description here...
  *
- * @param string $questionids list of questionids
+ * @param array $questionids of question ids
  * @param object $newcontext the context to create the saved category in.
  * @param string $oldplace a textual description of the think being deleted,
  *      e.g. from get_context_name
@@ -571,7 +571,7 @@ function question_delete_activity($cm, $feedback=true) {
  * function also have to do other work, which is why you should not call this method
  * directly from outside the questionbank.
  *
- * @param string $questionids a comma-separated list of question ids.
+ * @param array $questionids of question ids.
  * @param integer $newcategoryid the id of the category to move to.
  */
 function question_move_questions_to_category($questionids, $newcategoryid) {
diff --git a/question/category_class.php b/question/category_class.php
index 8881ce428a2..07c2d91be93 100644
--- a/question/category_class.php
+++ b/question/category_class.php
@@ -360,7 +360,7 @@ class question_category_object {
         global $DB;
         $questionids = $DB->get_records_select_menu('question',
                 'category = ? AND (parent = 0 OR parent = id)', array($oldcat), '', 'id,1');
-        question_move_questions_to_category($questionids, $newcat);
+        question_move_questions_to_category(array_keys($questionids), $newcat);
     }
 
     /**