(defvar gnus-prevent-distraction-prevention nil
  "If t, do not prevent distraction.")
(defvar gnus-distraction-prevention-include-ticked t
  "If t, groups with ticked articles will always be displayed.")
(setq gnus-distraction-threshold 1)

(defun gnus-distraction-prevention-check (info)
  "Return t if group has more than gnus-distraction-threshold unread articles.
If gnus-distraction-prevention-include-ticked is t, groups with ticked articles will always be displayed."
  ;(debug)
  (let* ((group (car info))
         (threshold (or 
                     (if gnus-prevent-distraction-prevention
                         1
                       nil)
                     (gnus-group-find-parameter group
                                                'gnus-distraction-threshold)
                     gnus-distraction-threshold))
         (unread (or (gnus-group-unread group)
                     0))
         (ticked (assoc 'tick (gnus-info-marks info))))
    ;; if unread is t, the group is not opened
    (if (eq unread t)
        (setq unread 0))
    ;;(message (concat "threshold for " group " is "
    ;;                 (number-to-string threshold)))
    (or (and gnus-distraction-prevention-include-ticked
             ticked)
        (>= unread threshold))))

(defun gnus-distraction-prevention-toggle ()
  "Toggle between distraction prevention and no distraction prevention."
  (interactive)
  (let ((message))
    (if gnus-prevent-distraction-prevention
        (progn
          (setq gnus-prevent-distraction-prevention nil
                message "on"))
      (setq gnus-prevent-distraction-prevention t
            message "off"))
    (gnus-group-list-groups)
    (message (concat "Distraction prevention is " message "."))))

(defun gnus-distraction-tick-toggle ()
  "Toggle between displaying groups with ticked articles or not."
  (interactive)
  (let ((message))
    (if gnus-distraction-prevention-include-ticked
        (progn
          (setq gnus-distraction-prevention-include-ticked nil
                message "on"))
      (setq gnus-distraction-prevention-include-ticked t
            message "off"))
    (gnus-group-list-groups)
    (message (concat "Ticked distraction prevention is " message "."))))

(define-key gnus-group-mode-map (kbd "C-c d")
  'gnus-distraction-prevention-toggle)
(define-key gnus-group-mode-map (kbd "C-c t")
  'gnus-distraction-tick-toggle)