A Pjax response may have notification to display (e.g. when updating a ContentType). Those messages need to be dispatched by the PlatformUI notification system.
In a Pjax response, the notification should be a new block defining both the notification text and and the notification state. For instance:
Where the data-state attribute is one of the supported notification states in the application (it's only a matter of CSS, see https://github.com/ezsystems/PlatformUIBundle/blob/master/Resources/public/css/theme/views/notification.css). The currently supported states are: