Idle: This is an extension for Vaadin to track user activity / user inactivity. Inactivity is checked by tracking mouse and keyboard moves in the whole window. After user is idle for a given period a CSS class is applied to <body> element and optionally an event is sent to the rest of the application.
This extension can be used to hide unnecessary controls when user is not active, or give a notification and/or prevent user session from expiring. 
The following CSS class names are used:
- body.userinactive
- body.useractive
These can be used to chance the look and feel: animate, show or hide, gray-out or just disable some elements with CSS. This works best with ‘Valo’ theme.
If a listener is also given, it will be notified on activity changes. This can be used to trigger some UI changes or start/stop background tasks.
Idle timeout can be configured in milliseconds. Default is 5000 (i.e. 5 seconds).