Improve docs demo

docs/data/material/components/app-bar/app-bar.md

@@ -160,4 +160,4 @@ You can override this behavior by setting the `enableColorOnDark` prop to `true`
 
 The [DashboardLayout](https://mui.com/toolpad/core/react-dashboard-layout/) component from `@toolpad/core` is the starting point for dashboarding applications. It takes care of application layout, theming, navigation, and more. An example usage of this component:
 
-{{"demo": "DashboardLayoutBasic.js", "height": 400, "iframe": true, "bg": "inline", "defaultExpanded": false}}
+{{"demo": "DashboardLayoutBasic.js", "height": 400, "iframe": true, "defaultExpanded": false}}