I recently upgraded to Emacs 25.1.2, and transient-mark-mode no longer works properly - sometimes.

The behavior I see is that pressing C-spc and moving the cursor to select an area of text doesn't automatically highlight the area. If I move to another window and return, or switch to a different window and come back, I see the selection highlighted.

I also see the section highlighted if the cursor comes across a parenthesis. Since I have show-paren-mode turned on, the parens get highlighted, and the selection also gets highlighted.

It's suddenly working as expected as I type this, but it wasn't working for the past couple of days, in spite of restarts.

How do I debug what might be happening?

  • Basic troubleshooting. If you can reproduce this with emacs -Q it's an actual bug that ought to be reported to the Emacs maintainers.
    – Tyler
    Feb 3, 2017 at 14:27
  • The problem hasn't recurred yet. But once it does, I will give that a shot. Feb 5, 2017 at 9:13

1 Answer 1


I had exactly the same issue. In my case the issue was caused by using package "expand-region". A workaround for the issue is to add (setq shift-select-mode nil) to Emacs config file. For more details, see https://github.com/magnars/expand-region.el/issues/229 (and related issues #220, #225).

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