diff --git a/docs/setup.md b/docs/setup.md
index c8e6d0ad..a9aba72b 100644
--- a/docs/setup.md
+++ b/docs/setup.md
@@ -110,6 +110,8 @@ The Settings Page is available from the **File** menu under **Settings** (Click
 - **Options**
    - **Hide Menu Bar** (Windows, Linux)
       - This option hides the menu bar. Press "Alt" to show it.
+   - **Show Icon on Menu Bar** (OS X)
+      - The icon apeears on menu bar to indicate whether there are new messages or mention.
    - **Allow insecure contents**
       - If your team is hosted on `https://`, images with `http://` are not rendered by default.
         This option allows such images to be rendered, but please be careful for security.