Index: branches/5.1.x/core/units/categories/categories_event_handler.php
===================================================================
diff -u -r13581 -r13811
--- branches/5.1.x/core/units/categories/categories_event_handler.php	(.../categories_event_handler.php)	(revision 13581)
+++ branches/5.1.x/core/units/categories/categories_event_handler.php	(.../categories_event_handler.php)	(revision 13811)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: categories_event_handler.php 13581 2010-05-19 07:33:23Z alex $
+* @version	$Id: categories_event_handler.php 13811 2010-07-07 09:41:05Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -1304,7 +1304,9 @@
 			$object =& $event->getObject();
 			/* @var $object kDBItem */
 
-			$object->SetDBField('ModifiedById', $this->Application->RecallVar('user_id'));
+			if ($object->GetChangedFields()) {
+				$object->SetDBField('ModifiedById', $this->Application->RecallVar('user_id'));
+			}
 
 			$this->_beforeItemChange($event);
 		}
@@ -1556,8 +1558,10 @@
 
 			$now = adodb_mktime();
 
-			$object->SetDBField('Modified_date', $now);
-			$object->SetDBField('Modified_time', $now);
+			if ($object->GetChangedFields()) {
+				$object->SetDBField('Modified_date', $now);
+				$object->SetDBField('Modified_time', $now);
+			}
 
 			$object->setRequired('PageCacheKey', $object->GetDBField('OverridePageCacheKey'));
 			$object->SetDBField('Template', $this->_stripTemplateExtension( $object->GetDBField('Template') ));