My tmux config

.tmux.conf

set-option -g default-command "reattach-to-user-namespace -l sh"

# change bind key to C-a
unbind -n C-b
set-option -g prefix C-a
bind-key C-a send-prefix

# disable mouse
bind-key m \
    set -g mode-mouse off \;\
    set -g mouse-resize-pane off \;\
    display 'Mouse Off'

# enable mouse
bind-key M \
    set -g mode-mouse on \;\
    set -g mouse-resize-pane on \;\
    display 'Mouse On'

setw -g mode-keys vi
bind-key -t vi-copy 'v' begin-selection
bind-key -t vi-copy 'y' copy-selection
bind -r C-h resize-pane -L
bind -r C-j resize-pane -D
bind -r C-k resize-pane -U
bind -r C-l resize-pane -R

# enable mouse
set-window-option -g mode-mouse on
set-option -g mouse-resize-pane on
# set-option -g mouse-select-pane off
# set-option -g mouse-select-window off