? triggering_element.patch
Index: modules/file/file.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/file/file.module,v
retrieving revision 1.50
diff -u -p -r1.50 file.module
--- modules/file/file.module    29 Dec 2010 04:35:23 -0000      1.50
+++ modules/file/file.module    31 Dec 2010 17:46:21 -0000
@@ -533,7 +533,7 @@ function file_managed_file_validate(&$el
   // If referencing an existing file, only allow if there are existing
   // references. This prevents unmanaged files from being deleted if this
   // item were to be deleted.
-  $clicked_button = end($form_state['clicked_button']['#parents']);
+  $clicked_button = end($form_state['triggering_element']['#parents']);
   if ($clicked_button != 'remove_button' && !empty($element['fid']['#value'])) {
     if ($file = file_load($element['fid']['#value'])) {
       if ($file->status == FILE_STATUS_PERMANENT) {