Index: branches/5.2.x/core/units/languages/languages_item.php
===================================================================
diff -u -N -r14244 -r14572
--- branches/5.2.x/core/units/languages/languages_item.php	(.../languages_item.php)	(revision 14244)
+++ branches/5.2.x/core/units/languages/languages_item.php	(.../languages_item.php)	(revision 14572)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: languages_item.php 14244 2011-03-16 20:53:41Z alex $
+* @version	$Id: languages_item.php 14572 2011-09-20 15:25:49Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -22,10 +22,24 @@
 			return $this->Conn->GetOne($sql) + 1;
 		}
 
+		/**
+		 * Set's current language as new primary and return previous primary language
+		 *
+		 * @param bool $reset_primary
+		 * @param bool $admin_language
+		 * @return int
+		 */
 		function setPrimary($reset_primary = true, $admin_language = false)
 		{
+			$prev_primary = false;
 			$primary_field = $admin_language ? 'AdminInterfaceLang' : 'PrimaryLang';
+
 			if ($reset_primary) {
+				$sql = 'SELECT ' . $this->IDField . '
+						FROM ' . $this->TableName . '
+						WHERE ' . $primary_field . ' = 1';
+				$prev_primary = $this->Conn->GetOne($sql);
+
 				$sql = 'UPDATE '.$this->TableName.'
 						SET '.$primary_field.' = 0';
 				$this->Conn->Query($sql);
@@ -39,9 +53,38 @@
 			// in case, when Update method is called for this langauge object
 			$this->SetDBField($primary_field, 1);
 			$this->SetDBField('Enabled', 1);
+
+			// increment serial by hand, since no Update method is called
+			$this->Application->incrementCacheSerial($this->Prefix);
+			$this->Application->incrementCacheSerial($this->Prefix, $this->GetID());
+
+			return $prev_primary;
 		}
 
 		/**
+		 * Copies missing data on current language from given language
+		 *
+		 * @param int $from_language
+		 */
+		function copyMissingData($from_language)
+		{
+			if ( !is_numeric($from_language) || ($from_language == $this->GetID()) ) {
+				// invalid or same language
+				return ;
+			}
+
+			$ml_helper =& $this->Application->recallObject('kMultiLanguageHelper');
+			/* @var $ml_helper kMultiLanguageHelper */
+
+			$to_language = $this->GetID();
+			$this->Application->UnitConfigReader->ReReadConfigs();
+
+			foreach ($this->Application->UnitConfigReader->configData as $prefix => $config_data) {
+				$ml_helper->copyMissingData($prefix, $from_language, $to_language);
+			}
+		}
+
+		/**
 		 * Allows to format number according to regional settings
 		 *
 		 * @param float $number