diff --git a/libs/plugins/modifier.default.php b/libs/plugins/modifier.default.php
index b0daa7d2..ad4e842d 100644
--- a/libs/plugins/modifier.default.php
+++ b/libs/plugins/modifier.default.php
@@ -10,7 +10,7 @@
  */
 function smarty_modifier_default($string, $default = '')
 {
-    if (empty($string))
+    if (!isset($string) || $string == '')
         return $default;
     else
         return $string;
diff --git a/plugins/modifier.default.php b/plugins/modifier.default.php
index b0daa7d2..ad4e842d 100644
--- a/plugins/modifier.default.php
+++ b/plugins/modifier.default.php
@@ -10,7 +10,7 @@
  */
 function smarty_modifier_default($string, $default = '')
 {
-    if (empty($string))
+    if (!isset($string) || $string == '')
         return $default;
     else
         return $string;