Tmux: prevent closing final window for shell session via standard bind

configs/tmux.conf

@@ -27,8 +27,11 @@ bind-key l select-pane -R
 unbind o
 unbind c
 bind-key o new-window
-bind-key c kill-window
 
+# bind-key c kill-window
+bind-key c if-shell -F '#{==:#{session_windows},1}' \
+  'display-message "This is the last window, cannot close it."' \
+  'kill-window'
 
 # Window Renaming
 set-option -g allow-rename off