Comment by mfontani

I had a long battle with making kitty work with tmux. I settled on the following in ~/.tmux.conf, before moving to wezterm for good. Maybe it fixes things for you, too:

    set -g default-terminal xterm-256color
    set-option -sa terminal-overrides ',xterm-kitty:RGB'
    set-option -ga terminal-overrides ",xterm*:Tc:smcup@:rmcup@"
    set-option -ga terminal-overrides ",screen*:Tc:smcup@:rmcup@"
    set-option -ga terminal-overrides ",tmux*:Tc:smcup@:rmcup@"

I honestly don't know whether all are needed, or only some. But with these, it worked well for me.