Index: modules/system/system.module
===================================================================
--- modules/system/system.module	(revision 20)
+++ modules/system/system.module	(working copy)
@@ -531,7 +531,7 @@
  */
 function system_init() {
   // Use the administrative theme if the user is looking at a page in the admin/* path.
-  if (arg(0) == 'admin' || (variable_get('node_admin_theme', '0') && arg(0) == 'node' && (arg(1) == 'add' || arg(2) == 'edit'))) {
+  if (arg(0) == 'admin' || (variable_get('node_admin_theme', '0') && arg(0) == 'node' && (arg(1) == 'add' || arg(2) == 'edit' || arg(2) == 'delete'))) {
     global $custom_theme;
     $custom_theme = variable_get('admin_theme', '0');
     drupal_add_css(drupal_get_path('module', 'system') .'/admin.css', 'module');