Breaking: #73044 - JSON for ClickMenu in Backend
See forge#73044
Description
The ClickMenu in the TYPO3 Backend now uses JSON to transport data between the server and the client.
Before, a proprietary <t3ajax> syntax with XML was used to transport the contents of the ClickMenu.
Impact
Using ClickMenu to implement a custom ClickMenu JavaScript handler instead of the default ClickMenu.js could result in unexpected behaviour.
Affected Installations
Installations with extensions that use custom ClickMenu.js behaviour.
Migration
Adapt the custom code to handle JSON responses instead of XML responses.