anchor.diff:    (if (quri:uri= url-or-node (url buffer))
         (echo "History entry is already the current URL.")
         (buffer-load url-or-node)))
  -
  -(defun conservative-history-filter (web-mode)
  -  #'(lambda (node)                      ; TODO: Pass owner?
  -      (with-data-access (history (history-path (buffer web-mode)))
  -        (and (conservative-history-movement-p web-mode)
  -             (not (htree::owned-parent (htree:current-owner history)
  -                                       node))))))
   
   (define-command history-backwards (&optional (buffer (current-buffer)))
     "Go to parent URL in history."
  
positive.code:             (htree:forward history)
              (htree:current-owner-node history))))
      (load-url-if-not-current new-node)))
  
  (defun dead-history-filter (web-mode)
    #'(lambda (node)
        (and (history-forwards-to-dead-history-p web-mode)
             (str:emptyp (id (htree:value node))))))
  
  (defun history-backwards-suggestion-filter (&optional (buffer (current-buffer)))
    "Suggestion function over all parent URLs."
  
negative.code:   "Scroll to top if no input element is active, forward event otherwise."
    (call-non-input-command-or-forward #'scroll-to-top :buffer buffer))
  
  (defun load-url-if-not-current (url-or-node &optional (buffer (current-buffer)))
    "Go to HISTORY-NODE's URL."
    (unless (quri:uri-p url-or-node)
  