diff --git a/library/Icinga/Data/Filter/FilterChain.php b/library/Icinga/Data/Filter/FilterChain.php
index c7697b7ad..e86f6fec9 100644
--- a/library/Icinga/Data/Filter/FilterChain.php
+++ b/library/Icinga/Data/Filter/FilterChain.php
@@ -184,7 +184,7 @@ abstract class FilterChain extends Filter
     public function addFilter(Filter $filter)
     {
         $this->filters[] = $filter;
-        $filter->setId($this->getId() . '-' . (count($this->filters)));
+        $filter->setId($this->getId() . '-' . $this->count());
     }
 
     public function &filters()
@@ -192,6 +192,11 @@ abstract class FilterChain extends Filter
         return $this->filters;
     }
 
+    public function count()
+    {
+        return count($this->filters);
+    }
+
     public function __clone()
     {
         foreach ($this->filters as & $filter) {