Index: branches/5.1.x/core/kernel/db/cat_tag_processor.php
===================================================================
diff -u -N -r13789 -r13936
--- branches/5.1.x/core/kernel/db/cat_tag_processor.php	(.../cat_tag_processor.php)	(revision 13789)
+++ branches/5.1.x/core/kernel/db/cat_tag_processor.php	(.../cat_tag_processor.php)	(revision 13936)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: cat_tag_processor.php 13789 2010-06-15 21:00:24Z alex $
+* @version	$Id: cat_tag_processor.php 13936 2010-09-13 07:05:58Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -433,18 +433,19 @@
 		{
 			$list =& $this->GetList($params);
 			$user_sorting_start = $this->getUserSortIndex();
-
-			$sorting_field = $list->GetOrderField($user_sorting_start);
-			$sorting = strtolower($sorting_field . '|' . $list->GetOrderDirection($user_sorting_start));
-
+	
+			list ($sorting_field, $sorting_direction) = explode('|', $params['sorting']);
+			$sorting_field = preg_replace('/^l[\d]+_(.*)/', '\\1', $sorting_field); // remove language prefix (if any)
 			$field_options = $list->GetFieldOptions($sorting_field);
+	
 			if (array_key_exists('formatter', $field_options) && $field_options['formatter'] == 'kMultiLanguage') {
-				// remove language prefix
-				$sorting = preg_replace('/^l[\d]+_(.*)/', '\\1', $sorting);
-				$params['sorting'] = preg_replace('/^l[\d]+_(.*)/', '\\1', $params['sorting']);
+				// remove language prefix for $sorting_field
+				$params['sorting'] = $list->getMLSortField($sorting_field) . '|' . $sorting_direction;
 			}
-
-			return $sorting == strtolower($params['sorting']) ? $params['selected'] : '';
+	
+			$current_sorting = $list->GetOrderField($user_sorting_start) . '|' . $list->GetOrderDirection($user_sorting_start);
+	
+			return strtolower($current_sorting) == strtolower($params['sorting']) ? $params['selected'] : '';
 		}
 
 		function CombinedSortingDropDownName($params)
Index: branches/5.1.x/core/kernel/db/dblist.php
===================================================================
diff -u -N -r13885 -r13936
--- branches/5.1.x/core/kernel/db/dblist.php	(.../dblist.php)	(revision 13885)
+++ branches/5.1.x/core/kernel/db/dblist.php	(.../dblist.php)	(revision 13936)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: dblist.php 13885 2010-08-28 21:31:21Z alex $
+* @version	$Id: dblist.php 13936 2010-09-13 07:05:58Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -702,9 +702,11 @@
 	{
 		// original multilanguage field - convert to current lang field
 		$formatter = isset($this->Fields[$field]['formatter']) ? $this->Fields[$field]['formatter'] : false;
+
 		if ($formatter == 'kMultiLanguage' && !isset($this->Fields[$field]['master_field'])) {
-			$lang = $this->Application->GetVar('m_lang');
-			$field = 'l'.$lang.'_'.$field;
+			// for now kMultiLanguage formatter is only supported for real (non-virtual) fields
+			$is_expression = true;
+			$field = $this->getMLSortField($field);
 		}
 
 		if (!isset($this->Fields[$field]) && $field != 'RAND()' && !$is_expression) {
@@ -715,6 +717,23 @@
 	}
 
 	/**
+	 * Returns expression, used to sort given multilingual field
+	 *
+	 * @param string $field
+	 * @return string
+	 */
+	function getMLSortField($field)
+	{
+		$table_name = '`' . $this->TableName . '`';
+		$lang = $this->Application->GetVar('m_lang');
+		$primary_lang = $this->Application->GetDefaultLanguageId();
+
+		$ret = 'IF(COALESCE(%1$s.l' . $lang . '_' . $field . ', ""), %1$s.l' . $lang . '_' . $field . ', %1$s.l' . $primary_lang . '_' . $field . ')';
+
+		return sprintf($ret, $table_name);
+	}
+
+	/**
 	* Removes all order fields
 	*
 	* @access public