[CLIENT] Cant select a champion after completing a mission to unlock one.

I try to hit select and right before my cursor gets there it goes away, making me unable to select a champion for my reward. I am not the only one this happens to. Please fix :) Also, i have tried logging out and back in many times, restarting/uninstalling LoL Client dozens of times, and nothing has worked. I have had this bug for about a week, but its been around for over a month.