anchor.diff:     (buffer :initarg :buffer :accessor buffer :initform nil)
      (prompter:constructor
       (lambda (source)
  -      (with-data-unsafe (history (history-path (buffer source)))
  +      (with-history (history (buffer source))
           (funcall (if (conservative-history-movement-p (find-mode (buffer source) 'web-mode))
                        #'htree:all-contiguous-owned-parents
                        #'htree:all-parents)
  
positive.code:   "Open a new buffer displaying the whole history branch the current buffer is on."
    (nyxt::with-current-html-buffer (output-buffer "*History*"
                                                   'nyxt/history-tree-mode:history-tree-mode)
      (with-data-unsafe (history (history-path (current-buffer)))
        (let ((mode (find-submode output-buffer 'nyxt/history-tree-mode:history-tree-mode))
              (tree (spinneret:with-html-string
                      (:ul (:raw (htree:map-tree
  
negative.code:    (buffer :initarg :buffer :accessor buffer :initform nil)
     (prompter:constructor
      (lambda (source)
        (with-history (history (buffer source))
          (funcall (if (conservative-history-movement-p (find-mode (buffer source) 'web-mode))
                       (alex:compose #'htree:owned-children #'htree:current-owner)
                       (alex:compose #'htree:children #'htree:current-owner-node))
  