diff --git a/lisp/org-src.el b/lisp/org-src.el
index 26cd533f14..59d8ee305a 100644
--- a/lisp/org-src.el
+++ b/lisp/org-src.el
@@ -171,6 +171,7 @@ Values that modify the window layout (reorganize-frame, split-window-below,
 split-window-right) will restore the layout after exiting the edit buffer."
   :group 'org-edit-structure
   :type '(choice
+          (const plain)
 	  (const current-window)
 	  (const split-window-below)
 	  (const split-window-right)