[CLIENT] Frozen Login Screen

Starting today I've had this happen twice:

When I go to log in after typing my username and password and clicking Log In the league screen gets this weird bar in the middle, clears my password, and then stops working. When I hover it with my mouse the cursor shows the "working" symbol. The animation in the background keeps playing but nothing happens. Closing (it closes promptly and without a crash report) and then reopening makes the problem go away and I can log in as normal.

Here's a screenshot of what the frozen screen looks like... http://imgur.com/AKyq6RR