Hello, I found that commit 1014296344a75fa08e0a8814e4fbbd767e7eba4c brought some bugs. Step to reproduce (In vanilla Emacs, with latest org-mode): 1. Set these variables. (setq org-src-content-indentation 4) (setq org-src-preserve-indentation nil) 2. Try to comment some lines in a source block. For example, line 1 and 2. #+begin_src emacs-lisp (setq foo 1) (setq bar 2) (setq buz 3) #+end_src Expected: #+begin_src emacs-lisp ;; (setq foo 1) ;; (setq bar 2) (setq buz 3) #+end_src Got: #+begin_src emacs-lisp ;; (setq foo 1) ;; (setq bar 2) ;; (setq bu z 3) #+end_src Then I found that there is a problem in function `org-comment-or-uncomment-region` in lisp/org.el. in func `org-comment-or-uncomment-region` : #+begin_src emacs-lisp (let ((offset (- end beg))) (save-excursion (goto-char beg) (org-babel-do-in-edit-buffer (comment-or-uncomment-region (point) (+ offset (point)))))) #+end_src the value of `offset` is wrong, it became `Expected_Value + Max_Common_Indent * Lines_To_Comment`, in the example which is 8 chars more than expected. Thanks.