anchor.diff:                 '((* :font-family "monospace,monospace"
                       :font-size "14px"
                       :line-height "18px")
  -                 (body :border-top "4px solid dimgray"
  +                 (body :border-top "3px solid dimgray"
                          :margin "0"
                          :padding "0 6px")
                    ("#prompt-area"
  
positive.code:                   :background-color "#E8E8E8"
                    :width "100%"
                    :autofocus "true")
                   (".source-name"
                    :color "white"
                    :padding-left "5px"
  
negative.code:     ;; TODO: Only print `active-properties'.
      (flet ((source->html (source)
               (markup:markup
                (:div :class "source-name" (:span :class "source-glyph" "⛯") (prompter:name source))
                (:table :class "source-content"
                 (:tr
                  (loop with property-sample = (if (first (prompter:suggestions source)) ; TODO: Instead, ensure that suggestions always has an element?
                                                   (prompter:properties (first (prompter:suggestions source)))
  