diff --git a/demo/src/index.js b/demo/src/index.js
index f84bf1b3a8e5881c6b2b053de2330a31d1254685..ef6831b6f8582d6d933a54005469f9c38414986d 100644
--- a/demo/src/index.js
+++ b/demo/src/index.js
@@ -9,7 +9,7 @@ const config = {
   annotation: {
     adapter: (canvasId) => new LocalStorageAdapter(`localStorage://?canvasId=${canvasId}`),
     // adapter: (canvasId) => new AnnototAdapter(canvasId, endpointUrl),
-    exportLocalStorageAnnotations: false,
+    exportLocalStorageAnnotations: false, // display annotation JSON export button
   },
   id: 'demo',
   window: {