diff --git a/libraries/messages.inc.php b/libraries/messages.inc.php
index 640a21aee..5a8090a2e 100644
--- a/libraries/messages.inc.php
+++ b/libraries/messages.inc.php
@@ -1426,7 +1426,7 @@ $strStrucExcelCSV = __('CSV for MS Excel');
 $strStrucNativeExcel = __('Native MS Excel format');
 $strStrucOnly = __('Structure only');
 $strStructPropose = __('Propose table structure');
-$strStructureDiff = 'Structure Difference' ;
+$strStructureDiff = __('Structure Difference');
 $strStructureForView = __('Structure for view');
 $strStructureLC = __('structure');
 $strStructure = __('Structure');