How to add GitHub registry to Docker Manager?

[Mordac85]

I've tried adding https://ghcr.io to the registry in Docker Manager, but a search still only returns items from Docker Hub. Am I doing something wrong?
Image 1: registry config
Image 2: activate/launch registry (??)
Image 3: search results for Homepage, which should be ghcr.io/gethomepage/homepage

[TMLyy]

This feature is not available for the time being, and only the current default registry can be used.