           (setf (timeline-tools-entry-start-time entry-2) middle))))))
 
 (defun timeline-tools-transform-timeline (timeline)
-  "Return timeline from files, after application of
-`timeline-tools-filter-functions’."
+  "Return result of filtering TIMELINE.
+Filtering is done by applying all functions from
+`timeline-tools-filter-functions’, in order."
   (-reduce-from (lambda (tl f)
                   (funcall f tl))
                 timeline

        (push (cdr clock-line) inverted-timeline)
        (push (car clock-line) inverted-timeline))

      (setq inverted-timeline (-partition 2 (rest (reverse inverted-timeline))))

      ;; This is inefficient, but see comment in
      ;; `timeline-tools-copy-clocklines’ for rationale.

      (timeline-tools-next-line))))

(defun timeline-tools-reparse-timeline ()
  "Parse timeline from files again and redraw current display.
Updates category properties before constructing the new timeline."
  (interactive)
  (dolist (file timeline-tools--current-files)
