Index: units/helpers/category_helper.php
===================================================================
--- units/helpers/category_helper.php	(revision 13951)
+++ units/helpers/category_helper.php	(working copy)
@@ -387,31 +387,43 @@
 		 */
 		function _getChildren($parent_category_id, $language_count)
 		{
-			$id_field = $this->Application->getUnitOption('c', 'IDField');
+			static $items_by_parent = null, $parent_mapping = null;
 
-			// get category children + parent category
-			$sql = 'SELECT *
-					FROM '.$this->Application->getUnitOption('c', 'TableName').'
-					WHERE ParentId = '.$parent_category_id.' OR '.$id_field.' = '.$parent_category_id.'
-					ORDER BY Priority DESC';
-			$categories = $this->Conn->Query($sql, $id_field);
+			if ( !isset($items_by_parent) ) {
+				$fields = $items_by_parent = Array ();
 
-			$parent_data = $categories[$parent_category_id];
-			unset($categories[$parent_category_id]);
+				for ($i = 1; $i <= $language_count; $i++) {
+					$fields[] = 'l' . $i . '_Name';
+				}
 
-			// no children for this category
-			$data = Array ('id' => $parent_data[$id_field], 'children' => false, 'ThemeId' => $parent_data['ThemeId']);
-			for ($i = 1; $i <= $language_count; $i++) {
-				$data['l'.$i.'_Name'] = $parent_data['l'.$i.'_Name'];
-			}
+				$sql = 'SELECT CategoryId AS id, ' . implode(', ', $fields) . ', ParentId, ThemeId
+						FROM ' . $this->Application->getUnitOption('c', 'TableName') . '
+						ORDER BY Priority DESC';
+				$items = $this->Conn->Query($sql, 'id');
 
-			if (!$categories) {
-				// no children
-				return $data;
+				foreach ($items as $item_id => $item_data) {
+					$item_parent_id = $item_data['ParentId'];
+					unset($item_data['ParentId']);
+
+					if ( !array_key_exists($item_parent_id, $items_by_parent) ) {
+						$items_by_parent[$item_parent_id] = Array ();
+					}
+
+					$item_data['children'] = false;
+					$parent_mapping[$item_id] = $item_parent_id;
+					$items_by_parent[$item_parent_id][$item_id] = $item_data;
+				}
 			}
 
-			// category has children
+			$data = $items_by_parent[ $parent_mapping[$parent_category_id] ][$parent_category_id];
+			$categories = array_key_exists($parent_category_id, $items_by_parent) ? $items_by_parent[$parent_category_id] : Array ();
+
 			foreach ($categories as $category_id => $category_data) {
+				if ($category_id == $parent_category_id) {
+					// don't process myself - prevents recursion
+					continue;
+				}
+
 				$data['children'][$category_id] = $this->_getChildren($category_id, $language_count);
 			}