JSF UI Deprecation
This requires to have the JSF UI addon installed on your server that is deprecated since Nuxeo Platform LTS 2019. Please refer to the Web UI documentation.
After you've installed it, a tab Tenant isolation is available in the Admin Center where you can enable or disable the tenant isolation.
If you are working on JSF UI (DEPRECATED), make sure to install the JSF UI version of this addon, available here.