Unable to pick champion

This is more a problem of the interface than a bug; if there's a more appropriate place for this post, please let me know. While I was in champ select, an error occurred but it happened quickly and I'm not entirely sure I'm remembering the sequence of events correctly, so if this isn't replicatable, try some slightly different permutations. I was banning in a draft game while trying to set up a masteries page. So, I banned Blitz and very quickly moved my mouse down and clicked on the masteries button. This caused the masteries box to pop up but the Blitz splash art was still there on the right hand side of the screen. Unfortunately, it was on top of the masteries box, and it covered the 'close window' button on the top right. The result was that I couldn't see the utility masteries, couldn't close the masteries pop-up, and couldn't choose a champ because the masteries pop-up was in the way. I know that normally the splash art being continuously on the screen is fixed by moving your mouse over another champion, but when you can't see any of the champions, it locks you out completely. I feel like this is a simple fix; make the masteries screen have a higher priority than the splash arts.