1 files changed, 1 insertions, 1 deletions

diff --git a/type/GenericStacked.class.php b/type/GenericStacked.class.php
index 5d1a556..fd6abc7 100644
--- a/type/GenericStacked.class.php
+++ b/type/GenericStacked.class.php
@@ -37,7 +37,7 @@ class Type_GenericStacked extends Type_Default {
                         if ($i == (count($sources)-1))
                                 $rrdgraph[] = sprintf('CDEF:area_%s=avg_%1$s', crc32hex($sources[$i]));
                         else
-                                $rrdgraph[] = sprintf('CDEF:area_%s=area_%s,avg_%1$s,+', crc32hex($sources[$i]), crc32hex($sources[$i+1]));
+                                $rrdgraph[] = sprintf('CDEF:area_%s=area_%s,avg_%1$s,ADDNAN', crc32hex($sources[$i]), crc32hex($sources[$i+1]));
                 }
 
                 $c = 0;