diff --git a/include/class_listing.inc b/include/class_listing.inc
index 1b387a821fcd353b2bca5cc17a0a198972e73b75..fdbce686f160ba5fb9738b7806dba7383588dd14 100644
--- a/include/class_listing.inc
+++ b/include/class_listing.inc
@@ -243,6 +243,7 @@ class listing {
         }
       }
     }
+    $this->categories = array_unique($this->categories);
 
     // Parse layout per column
     $this->colprops = $this->parseLayout($this->xmlData['table']['layout']);