Index: trunk/core/kernel/utility/formatters/multilang_formatter.php
===================================================================
diff -u -N -r7635 -r7702
--- trunk/core/kernel/utility/formatters/multilang_formatter.php	(.../multilang_formatter.php)	(revision 7635)
+++ trunk/core/kernel/utility/formatters/multilang_formatter.php	(.../multilang_formatter.php)	(revision 7702)
@@ -59,6 +59,12 @@
 			if ( getArrayValue($grid, 'Fields', $field_name) ) {
 				array_rename_key($grids[$name]['Fields'], $field_name, $lang_field_name);
 			}
+			// update sort fields - used for sorting and filtering in SQLs
+			foreach ($grid['Fields'] as $grid_fld_name => $fld_options) {
+				if (isset($fld_options['sort_field']) && $fld_options['sort_field'] == $field_name) {
+					$grids[$name]['Fields'][$grid_fld_name]['sort_field'] = $lang_field_name;
+				}
+			}
 		}
 		$this->Application->setUnitOption($object->Prefix, 'Grids', $grids);