Set the Default Sandbox Mode for apps
The default Sandbox mode determines whether apps are automatically isolated (in a sandbox) or not (embedded) in a Web Part page. You should apply a sandbox (isolate apps) if publishing apps into the Web Part Page typically changes the layout of the Web Part Page.
To set the default Sandbox mode
1. Login is as site administrator for the site collection or specific site.
2. Click Site Actions > Site Settings.
3. Click Mashup Sites for SharePoint Site Settings.
4. Clear or set the Default to Sandbox option and click OK.