diff --git a/prototype/UI/index.html b/prototype/UI/index.html
index 8e73a35f6..5b2e7c8f6 100644
--- a/prototype/UI/index.html
+++ b/prototype/UI/index.html
@@ -220,7 +220,12 @@
     loadJSON('diff.json', function (json) {
         var diff = diffFromJSON(json.diff);
         var before = diff.map(function(value) {
-            return value.before != null ? termToDOM(value.before, "before", json["before"]) : "";
+            var element;
+            if (value.before != null) {
+                element = termToDOM(value.before, "before", json["before"]);
+                element.classList.add("delete");
+            }
+            return element || "";
         });
         var after = diff.map(function(value) {
             return value.after != null ? termToDOM(value.after, "after", json["after"]) : "";