Unable to get Copilot Chat to use external AI agent (xAI)

I did not find it with a search, either in the forums or via the web/AI agents.

What I’m trying to do

I want to be able to use both the local agent and the xAI agent with the CoPilot Chat.

Things I have tried

Per the documentation, I have entered the key and selected the grok-4.5 model. However, the chat window gives me two drop downs, one only containing th elocal agents, the other containing the grok agent. The grok agent does not have a text box. (see image). Every query to the agent tells me that I am talking to the local agent & that I need to change the drop down. Perhaps I am confused, but it seems like these two menus should actually be one?

Asking this in the GitHub issues for whatever plugin this is will yield better results.

Thank you