[O] How to only show org-timer indicator on active mode-line not all mode-lines?

[address@hidden]

I setup org-timer indicator in mode-line with this.

(setq-default

 mode-line-format

 (quote

  (

   ;; org-timer

   (:eval

    (unless (not org-timer-countdown-timer)

      (propertize (let* ((rtime (decode-time

                                 (time-subtract

                                  (timer--time org-timer-countdown-timer)

                                  (current-time))))

                         (rmins (nth 1 rtime))

                         (rsecs (nth 0 rtime)))

                    (format "🕔 %d:%d" rmins rsecs))

                  'face '(:foreground "cyan" :weight bold)

                  'help-echo "org-timer")))

   )))

I hope this org-time indicator only show in active mode-line instead of all mode-lines.

I hope to find a general way which can add any extra indicator not just org-timer. I can just put my upper code without too much modification into that general way.

I also posted a post on Emacs.SE https://emacs.stackexchange.com/questions/26222/how-to-only-show-thing-in-active-mode-line-instead-of-all-mode-lines

How to do it?

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