diff --git a/blocks/navigation/block_navigation.php b/blocks/navigation/block_navigation.php
index 79b8086..e916b67 100644
--- a/blocks/navigation/block_navigation.php
+++ b/blocks/navigation/block_navigation.php
@@ -282,7 +282,7 @@ class block_navigation extends block_base {
      * @return string The truncated string
      */
     protected function trim_left($textlib, $string, $length) {
-        return '...'.$textlib->substr($string, $textlib->strlen($string)-$length);
+        return '...'.$textlib->substr($string, $textlib->strlen($string)-$length, $length);
     }
     /**
      * Truncate a string from the right