Here's a really nasty Emacs bug that has pained me for a long time. In tab-bar-mode with two tabs open (call them "tab X" and "tab Y,")

  1. Open tab X.
  2. Do C-f or a similar command that opens the minibuffer
  3. With the minibuffer open and selected/active switch to tab Y.
  4. Hit C-g to close the minibuffer.
  5. Observe that the window configuration of tab Y has been overwritten with the window configuration of tab X.

It took me an embarassingly long time to unpack this behavior. Ever since I started using Emacs (around emacs 27 era), I'd randomly have tabs dupe and I had no idea why. Now that I understand the problem, how do I fix it?


Some relevant info:

  • Consider providing more details - a recipe to reproduce, starting with emacs -Q (no init file). How are you switching to tab Y? What do you mean by the "window configuration of tab ___"? Please show such configurations.
    – Drew
    Commented Dec 30, 2023 at 22:26
  • Just checked and the steps to replicate this bug starting from emacs -Q are the same. Enter tab-bar-mode, create two tabs, open the minibuffer, switch tabs, close the minibuffer. The exact function to switch tabs is tab-bar-switch-to-next-tab Commented Dec 30, 2023 at 23:16
  • 2
    Any time you discover a bug in Emacs ("really nasty" or otherwise) you ought to M-x report-emacs-bug with all of the details, so that it's registered and can be fixed. Provide all the details and the recipe from emacs -Q in your bug report.
    – phils
    Commented Dec 31, 2023 at 1:09
  • "Window configuration" is one thing. But what is "window configuration of a" tab? That's what's not clear. In what way does a tab have its own window configuration?
    – Drew
    Commented Dec 31, 2023 at 2:46
  • Drew: in tab-bar-mode tabs are associated with window configurations. Selecting a tab restores the window configuration for that tab.
    – phils
    Commented Dec 31, 2023 at 7:33

1 Answer 1


Fortunately, this bug was fixed in Emacs 30 six months ago. Is it possible for you to upgrade to Emacs 30?

  • better to provide a link to the relevant bug report or commit to fix the bug
    – shynur
    Commented Dec 31, 2023 at 9:39
  • Second this, a link to a diff or bug report would be helpful Commented Dec 31, 2023 at 13:13
  • here is a link to the relevant bug report debbugs.gnu.org/64373
    – link0ff
    Commented Jan 2 at 15:12

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