diff --git a/ext/bg/js/json-schema.js b/ext/bg/js/json-schema.js
index 49f1e082..0ca1183e 100644
--- a/ext/bg/js/json-schema.js
+++ b/ext/bg/js/json-schema.js
@@ -134,7 +134,7 @@ class JsonSchemaProxyHandler {
                 const additionalProperties = schema.additionalProperties;
                 if (additionalProperties === false) {
                     return null;
-                } if (JsonSchemaProxyHandler.isObject(additionalProperties)) {
+                } else if (JsonSchemaProxyHandler.isObject(additionalProperties)) {
                     return additionalProperties;
                 } else {
                     return JsonSchemaProxyHandler._unconstrainedSchema;