Index: core/filter_api.php
===================================================================
--- core/filter_api.php	(revision 5719)
+++ core/filter_api.php	(working copy)
@@ -832,6 +832,8 @@
 
 	for( $i = 0;$i < count( $t_sort_fields );$i++ ) {
 		$c_sort = db_prepare_string( $t_sort_fields[$i] );
+		$c_dir = 'DESC' == $t_dir_fields[$i] ? 'DESC' : 'ASC';
+
 		if( !in_array( $t_sort_fields[$i], array_slice( $t_sort_fields, $i + 1 ) ) ) {
 
 			# if sorting by a custom field
@@ -849,9 +851,11 @@
 					$p_query_clauses['join'][] = "LEFT JOIN $t_custom_field_string_table $t_cf_table_alias ON $t_bug_table.id  = $t_cf_table_alias.bug_id AND $t_cf_table_alias.field_id = $t_custom_field_id";
 				}
 
-				$c_dir = 'DESC' == $t_dir_fields[$i] ? 'DESC' : 'ASC';
 				$p_query_clauses['order'][] = "$c_cf_alias $c_dir";
 			}
+			else {
+				$p_query_clauses['order'][] = $c_sort . " " . $c_dir;
+			}
 		}
 	}