Index: trunk/core/units/categories/categories_event_handler.php
===================================================================
diff -u -N -r8491 -r8562
--- trunk/core/units/categories/categories_event_handler.php	(.../categories_event_handler.php)	(revision 8491)
+++ trunk/core/units/categories/categories_event_handler.php	(.../categories_event_handler.php)	(revision 8562)
@@ -141,9 +141,15 @@
 
 		if ("$parent_cat_id" != 'any') {
 			if ($event->getEventParam('recursive')) {
-				$current_path = $this->Conn->GetOne('SELECT ParentPath FROM '.TABLE_PREFIX.'Category WHERE CategoryId='.$parent_cat_id);
-				$subcats = $this->Conn->GetCol('SELECT CategoryId FROM '.TABLE_PREFIX.'Category WHERE ParentPath LIKE "'.$current_path.'%" ');
-				$object->addFilter('parent_filter', 'ParentId IN ('.implode(', ', $subcats).')');
+				if ($parent_cat_id > 0) {
+					// not "Home" category
+					$sql = 'SELECT TreeLeft, TreeRight
+							FROM '.TABLE_PREFIX.'Category
+							WHERE CategoryId = '.$parent_cat_id;
+					$tree_indexes = $this->Conn->GetRow($sql);
+
+					$object->addFilter('parent_filter', TABLE_PREFIX.'Category.TreeLeft BETWEEN '.$tree_indexes['TreeLeft'].' AND '.$tree_indexes['TreeRight']);
+				}
 			}
 			else {
 				$object->addFilter('parent_filter', 'ParentId = '.$parent_cat_id);
Index: trunk/core/units/general/cat_event_handler.php
===================================================================
diff -u -N -r8546 -r8562
--- trunk/core/units/general/cat_event_handler.php	(.../cat_event_handler.php)	(revision 8546)
+++ trunk/core/units/general/cat_event_handler.php	(.../cat_event_handler.php)	(revision 8562)
@@ -360,9 +360,15 @@
 
 			if ((string) $parent_cat_id != 'any') {
 				if ($event->getEventParam('recursive')) {
-					$current_path = $this->Conn->GetOne('SELECT ParentPath FROM '.TABLE_PREFIX.'Category WHERE CategoryId='.$parent_cat_id);
-					$subcats = $this->Conn->GetCol('SELECT CategoryId FROM '.TABLE_PREFIX.'Category WHERE ParentPath LIKE "'.$current_path.'%" ');
-					$object->addFilter('category_filter', TABLE_PREFIX.'CategoryItems.CategoryId IN ('.implode(', ', $subcats).')');
+					if ($parent_cat_id > 0) {
+						// not "Home" category
+						$sql = 'SELECT TreeLeft, TreeRight
+								FROM '.TABLE_PREFIX.'Category
+								WHERE CategoryId = '.$parent_cat_id;
+						$tree_indexes = $this->Conn->GetRow($sql);
+
+						$object->addFilter('category_filter', TABLE_PREFIX.'Category.TreeLeft BETWEEN '.$tree_indexes['TreeLeft'].' AND '.$tree_indexes['TreeRight']);
+					}
 					$object->addFilter('primary_filter', 'PrimaryCat = 1');
 				}
 				else {
Index: trunk/core/units/categories/categories_config.php
===================================================================
diff -u -N -r8397 -r8562
--- trunk/core/units/categories/categories_config.php	(.../categories_config.php)	(revision 8397)
+++ trunk/core/units/categories/categories_config.php	(.../categories_config.php)	(revision 8562)
@@ -251,6 +251,8 @@
 									            'CreatedById'				=>	Array('type' => 'int', 'formatter' => 'kLEFTFormatter', 'options' => Array(-1 => 'root', -2 => 'Guest'),'left_sql'=>'SELECT %s FROM '.TABLE_PREFIX.'PortalUser WHERE `%s` = \'%s\'', 'left_key_field' => 'PortalUserId', 'left_title_field' => 'Login', 'not_null' => 1,'default' => 0),
 									            'ResourceId'				=>	Array('type' => 'int', 'default' => null),
 									            'ParentPath'				=>	Array('type' => 'string', 'default' => null),
+									            'TreeLeft'					=>	Array ('type' => 'int', 'not_null' => 1, 'default' => 0),
+    											'TreeRight'					=>	Array ('type' => 'int', 'not_null' => 1, 'default' => 0),
 									            'NamedParentPath'			=>	Array('type' => 'string', 'default' => null),
 									            'MetaDescription'			=>	Array('type' => 'string', 'default' => null),
 									            'HotItem'					=>	Array('type' => 'int', 'formatter' => 'kOptionsFormatter', 'options' => Array (2 => 'la_Auto', 1 => 'la_Always', 0 => 'la_Never'), 'use_phrases' => 1,  'not_null' => 1, 'default' => 2),