Index: plugin.php
===================================================================
--- plugin.php  (revision 10674)
+++ plugin.php  (working copy)
@@ -645,6 +645,8 @@
 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) )
                return $function;
@@ -654,10 +656,8 @@
                if ( !isset($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;
+                       $function[0]->wp_filter_id = $filter_id_count++;
                        $obj_idx .= $count;
-                       unset($count);
                } else
                        $obj_idx .= $function[0]->wp_filter_id;
                return $obj_idx;