add comment

jsonform.gadget.js

@@ -585,6 +585,7 @@
     } else {
       schema_p = schema_path;
     }
+    // XXX check oneOf anyOf allOf length >= 1 and generate exception if not
     if (schema.anyOf !== undefined) {
       return anyOf(g, schema.anyOf, schema_p + '/anyOf', path, schema);
     }