     (setq-local timeline-tools--current-time-start (+ 86400 timeline-tools--current-time-start))
     (setq-local timeline-tools--current-time-end (+ 86400 timeline-tools--current-time-end))
     (setq-local timeline-tools--current-timeline
-                (timeline-tools-get-transformed-timeline
-                 timeline-tools--current-time-start
-                 timeline-tools--current-time-end
-                 timeline-tools--current-files))
+                (timeline-tools-transform-timeline
+                 (timeline-tools-timeline
+                  timeline-tools--current-time-start
+                  timeline-tools--current-time-end
+                  timeline-tools--current-files)))
     (timeline-tools-redraw-timeline)))
 
 (defun timeline-tools-backward-day ()

interactively, START and END are queried with `org-read-date’."
  (interactive (list (org-read-date nil nil nil "Start time: ")
                     (org-read-date nil nil nil "End time: ")))
  (let* ((timeline (timeline-tools-get-transformed-timeline tstart tend files)))
    (let ((target-buffer (get-buffer-create " *Org Timeline*")))
      (with-current-buffer target-buffer
        (timeline-tools-mode)

    (with-current-buffer (get-file-buffer file)
      (org-refresh-category-properties)))
  (setq-local timeline-tools--current-timeline
              (timeline-tools-transform-timeline
               (timeline-tools-timeline
                timeline-tools--current-time-start
                timeline-tools--current-time-end
                timeline-tools--current-files)))
  (timeline-tools-redraw-timeline))

(defun timeline-tools-forward-day ()
