anchor.diff:                  (htree:backward-owned-parents history)
                   (htree:backward history))
               (htree:current-owner-node history))))
  -    (load-url-if-not-current new-node)))
  +    (load-history-url new-node
  +                      :message "No backward history.")))
   
   (define-command history-forwards (&optional (buffer (current-buffer)))
     "Go to forward URL in history."
  
positive.code:         ;; Same with `history-backwards-query'.
          (loop until (eq input (htree:current-owner-node history))
                      do (htree:forward history)))
        (load-url-if-not-current input))))
  
  (defun history-forwards-all-suggestion-filter (&optional (buffer (current-buffer)))
    "Suggestion function over children URL from all branches."
  
negative.code:           (with-data-access (history (history-path buffer))
              (htree:forward history)
              (htree:current-owner-node history))))
      (load-history-url new-node
                        :message "No forward history.")))
  
  (defun history-backwards-suggestion-filter (&optional (buffer (current-buffer)))
    "Suggestion function over all parent URLs."
  