The league chat keeps popping up whenever you reopen the league. Muting doesn't stop it from popping up, nor does X-ing it out, nor does minimizing it. Unless I'm doing something wrong, I don't think there's a way to stop it from popping up whenever you reopen the league.

I really wish we could just turn it off tbh ...

That's odd, the three buttons should:

X - Close the chat (exit, you don't show as online). This should persist until your next login.
(speaker icon) - Mutes the chat, so you don't hear it, but you are still online. This also should be persistent.
_ - this should minimize the chat so that it doesn't take up any meaningful space on the screen.

I would really like to be able to move / resize the chat window.

Or an option of turning it off ..