Change record status: 
Project: 
Introduced in branch: 
10.0.x
Introduced in version: 
10.0.10
Description: 

This change introduces a new data attribute data-drupal-ajax-container in the ajax system. It is used to indicate a collapsible element containing for ajax-enabled elements that might not be visible onscreen. This is useful for situations such as appending an ajax throbber to the visible container instead of the hidden triggering element inside it (added in https://www.drupal.org/node/3087950).

This attribute could potentially be used for focus management, too, such as scenarios where a contextual link opens a dialog, then when the dialog is closed, the triggering element is inside a collapsed element.

Example usage that allows ajax throbber to be rendered outside of the dropbutton tray:

<div class="dropbutton-wrapper" data-drupal-ajax-container>
Impacts: 
Module developers
Themers