diff --git a/prototype/UI/index.html b/prototype/UI/index.html
index 11597cf8e..42c11acd7 100644
--- a/prototype/UI/index.html
+++ b/prototype/UI/index.html
@@ -142,7 +142,7 @@
     }
 
     function Syntax(json, continuation) {
-        if (json.indexed != null) { this.indexed = json.map(continuation); }
+        if (json.indexed != null) { this.indexed = json.indexed.map(continuation); }
         if (json.keyed != null) { this.keyed = (new Dictionary(json.keyed)).map(continuation); }
         if (json.leaf != null) { this.leaf = json; }
         return this;