[client] masteries page not closing

After setting my runes and masteries, I opened up my masteries page to make sure it was the right selection. I looked at it for about 30 seconds without touching anything. When i closed it, the mastery page stayed open, like in the attachment. Nothing I could do would close it. Even after playing a game, and going to the post-game chat, the mastery page still remained, and continued to persist until I closed the program and reloaded it.

I seem to remember that, after about ten seconds of looking at my masteries, that all the icons lite up, like I still had mastery points to spend--though I did not. I don't remember anything else unusual, and I wasn't particularly looking for anything at the time. I seem to remember that happening however.