windows 10, emacs 26.1

I want to set I-search case sensitive mode. Before:

enter image description here

M-x isearch-toggle-case-fold


enter image description here

Now it's search in case sensitive mode. Nice.

But why it select text?

P.S. If I start by emacs -Q it's same result:

Here steps of reproduce:

  1. Start emacs -Q
  2. Input some text
  3. M-x isearch-toggle-case-fold
  4. C-s (isearch) HELLO
  5. C-g
  6. M-x isearch-toggle-case-fold
  7. and see result on step4.jpg

enter image description here enter image description here enter image description here enter image description here

  • You've probably had your mark set before you've started to search.
    – user12563
    Jul 30, 2019 at 13:17
  • @DoMiNeLa10 No, I'm not mark any text Jul 30, 2019 at 13:40
  • Do you see this with emacs -Q? If not, bisect your init file to find the culprit.
    – Drew
    Jul 30, 2019 at 15:19
  • @Drew Yes, I updated my post Jul 30, 2019 at 15:39
  • 1
    Sounds like a bug. Toggling case-sensitivity should not activate the region. Please consider filing a bug report, M-x report-emacs-bug, with a step-by-step recipe to reproduce the problem, starting with emacs -Q.
    – Drew
    Jul 30, 2019 at 19:21

1 Answer 1


Note, that I assume that isearch-toggle-case-fold is not supposed to be run outside of isearch-mode.

Cause of the effect: The highlighting belongs to the overlay stored in variable isearch-overlay generated or moved by function isearch-highlight.

isearch-highlight is called in isearch-update which is called in isearch-toggle-case-fold generated by isearch-define-mode-toggle.

The reason why isearch-update is used in isearch-define-mode-toggle is pretty clear. The change of the case sensitivity should have immediate effect.

But that only makes sense when we are in isearch-mode.

A conceptual fix would be:

(defun isearch-update-only-in-isearch-mode (fun &rest args)
  (when isearch-mode
    (apply fun args)))

(advice-add 'isearch-update :around #'isearch-update-only-in-isearch-mode)

But, maybe isearch-toggle-case-fold should actually throw an error when called outside of isearch-mode.

  • it looks like a bug in Emacs Aug 2, 2019 at 7:44

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