iTerm2 runs slowly when using tmux (without -CC control mode integration). It is clearly designed with the intention of using -CC.

However, I don't like the desktop window management of tmux windows/panes. I want tmux keyboard shortcuts and everything in a single iTerm2 window.

Is there a way to disable tmux integration in iTerm2 so that I can tmux without using -CC? And so that it won't lag?

If you are having difficulty trying to reproduce, try opening 2 tabs attached to the same tmux session. Compare it's I/O performance to the system terminal attached to the same tmux session.

1 Answer 1


Not a solution but a workaround - I discovered the incredible wezterm which is all I need. Here is my config.

hugh@Hughs-Mac-mini ~ % cat ~/.wezterm.lua
local wezterm = require 'wezterm';

wezterm.on("toggle-alert", function(window, pane)
        local overrides = window:get_config_overrides() or {}
        if not overrides.color_scheme then
                overrides.color_scheme = "Red Alert"
                overrides.color_scheme = nil

return {
  font = wezterm.font("IBM Plex Mono", {weight="Regular"}),
  font_size = 15,
  freetype_load_target = "Light",
  color_scheme = "AdventureTime",
  enable_tab_bar = false,
  default_cursor_style = "BlinkingBlock",
  keys = {
    {key="A", mods="CTRL", action=wezterm.action{EmitEvent="toggle-alert"}},

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