When using an external monitor/projector with Emacs, I use the Extend option (rather than Duplicate). Then I duplicate my work frame with C-x 5 2, that is make-frame-command, and I move the duplicate frame to the projector screen.

I further use activate hl-line-mode and

(setq cursor-in-non-selected-windows 'bar)

With this setting what I write on my laptop frame is mirrored on the projector frame, provided the it is set to the same buffer.

My problem is that I can't mirror the selection highlight, which unfortunately is shown only in the frame where I am actually writing/selecting.

Any possibility to do this?

2 Answers 2


I've asked a very similar question yesterday and stumbled upon your post only afterwards …

Nevertheless, this answer might help (could not yet test it on an external monitor): https://emacs.stackexchange.com/a/44905/20389


You could use OBS and project the frame to the display you want. This way, you could also record a video (optionally with your voice) should it make sense.

  • Did you understand my problem? I am just giving a presentation. I need to mirror the content of a single Emacs buffer (not the whole Emacs windows) to an Emacs frame displayed on an external monitor.
    – antonio
    Sep 12, 2018 at 8:39
  • Your question is phrased as if you wanted to mirror the whole frame.
    – user12563
    Sep 12, 2018 at 15:54

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