diff --git a/wp-includes/plugin.php b/wp-includes/plugin.php
index 2f7d4004a..0588bc9ac 100644
--- a/wp-includes/plugin.php
+++ b/wp-includes/plugin.php
@@ -665,13 +665,14 @@ function _wp_call_all_hook($args) {
  *
  * @global array $wp_filter Storage for all of the filters and actions
  * @param string $tag Used in counting how many hooks were applied
- * @param string|array $function Used for creating unique id
+ * @param callback $function Used for creating unique id
  * @param int|bool $priority Used in counting how many hooks were applied.  If === false and $function is an object reference, we return the unique id only if it already has one, false otherwise.
  * @param string $type filter or action
- * @return string Unique ID for usage as array key
+ * @return string|bool Unique ID for usage as array key or false if $priority === false and $function is an object reference, and it does not already have a uniqe id.
  */
 function _wp_filter_build_unique_id($tag, $function, $priority) {
 	global $wp_filter;
+	static $filter_id_count = 0;
 
 	// If function then just skip all of the tests and not overwrite the following.
 	if ( is_string($function) )
@@ -682,10 +683,8 @@ function _wp_filter_build_unique_id($tag, $function, $priority) {
 		if ( !isset($function[0]->wp_filter_id) ) {
 			if ( false === $priority )
 				return false;
-			$count = isset($wp_filter[$tag][$priority]) ? count((array)$wp_filter[$tag][$priority]) : 0;
-			$function[0]->wp_filter_id = $count;
-			$obj_idx .= $count;
-			unset($count);
+			$obj_idx .= isset($wp_filter[$tag][$priority]) ? count((array)$wp_filter[$tag][$priority]) : 0;
+			$function[0]->wp_filter_id = $filter_id_count++;
 		} else
 			$obj_idx .= $function[0]->wp_filter_id;
 		return $obj_idx;