Tmux messing with highlighting

[ElSargo]

Summary

When I run helix inside a tmux session all my comments get highlighted grey.

Then outside a tumx session the issue is gone...

Reproduction Steps

Install tmux using: sudo apt get tmux
Install helix with :
brew tap helix-editor/helix
brew install helix

open a supported file and make a comment
(this also happens in .toml files ect)

I have tried uninstalling both helix and tmux and removing all config files but I can't seem to find the cause of the issue

Helix log

log is empty

Platform

Linux ubuntu

Terminal Emulator

gnome40 terminal

Helix Version

helix 22.05 (27609f5)

[sudormrfbin]

It might be caused by your terminal not supporting italics (or tmux not picking up support for it from your terminal) since the comments are italicized. Could you try two other themes with and without italics and see what happens?

[christianfosli]

See https://github.com/tmux/tmux/wiki/FAQ#i-dont-see-italics-or-italics-and-reverse-are-the-wrong-way-round

It works for me with

set -g default-terminal "tmux-256color"

in my tmux.conf

[ElSargo]

That fixed it, thanks!

[hackaugusto]

Dropping a comment for Mac users arriving here through google:

• As of Monterey 12.6:
  • Mac is distributed with:

> ncurses5.4-config --version
5.7.20081102

• this version does not have tmux in its terminfo db:

> infocmp tmux
infocmp: couldn't open terminfo file (null).

• Since tmux 2.2 it supports italics, but the $TERM must be set to a variant matching the glob tmux* ref
  • This is the default as of 3.3a ref, which breaks everything on mac, so one must either generate the db by hand or set the term back to a variant of screen*
• The above means that tmux on macos does not support italics out-of-the-box, and can be tested with the following command:

> echo -e "\e[3mitalic\e[0m"

On iterm2 or alacritty this will render:

but in tmux, inside any of these virtual terminals:

this means that helix wont look right, like the screenshots on from OP or this:

inside tmux:

with only alacritty:

Possible fix: https://gpanders.com/blog/the-definitive-guide-to-using-tmux-256color-on-macos/

[Swoorup]

Dropping a comment for Mac users arriving here through google:

• As of Monterey 12.6:

  • Mac is distributed with:

> ncurses5.4-config --version
5.7.20081102

• this version does not have tmux in its terminfo db:

> infocmp tmux
infocmp: couldn't open terminfo file (null).

set -g default-terminal "tmux" fixed it for me,

[jerinjoy]

I followed the instructions in:
https://gpanders.com/blog/the-definitive-guide-to-using-tmux-256color-on-macos/

to set up the terminfo for tmux:

❯ exa -lh --git --sort=newest /Users/joy/.local/share/terminfo/74/tmux-256color
Permissions Size User Date Modified Name
.rw-r--r--@ 3.3k joy   7 Apr 22:29  /Users/joy/.local/share/terminfo/74/tmux-256color

and set "tmux" as my terminal. hx displays the colors correctly but I still get errors running some applications:

❯ git diff
WARNING: terminal is not fully functional
Press RETURN to continue

[Sackbuoy]

See https://github.com/tmux/tmux/wiki/FAQ#i-dont-see-italics-or-italics-and-reverse-are-the-wrong-way-round

It works for me with

set -g default-terminal "tmux-256color"

in my tmux.conf

Setting this caused Backspace Bad Behavior for me,
So I recommend setting

set -g default-terminal "xterm-256color"

instead

[muminoff]

This one worked for me.

Replace set -g default-terminal "xterm-256color" with following:

set-option -sa terminal-overrides ",xterm*:Tc"

Restart tmux.

[nmlt]

So I have this problem again, because I want to use tmux's control mode (tmux -CC). It's for integration with iTerm2 on Mac. Not using control mode it works and comments aren't highlighted, but as soon as iTerm2 manages the tmux session, italics seem to be broken again.

Anybody have an idea how to fix this?

[webdev23]

I had trouble loading Helix custom themes inside tmux/byobu, and the fix for me was to add exactly the following in ~/.byobu/tmux.conf:

set -g default-terminal "screen-256color"
set -ag terminal-overrides ",xterm-256color:RGB"