Cool (But Evil) Champion Select Glitch

Okay guys, so I recently encountered a bug in the champion select screen. If you click the pencil (to open the masteries page) and double-tap space bar, the entire masteries page screen freezes. This makes you unable to select a champ (if you haven't already) or change runes/masteries/summoner spells because the mastery screen is now blocking the way. It shows up as an empty gray box that you cannot exit out of, even if someone dodges. #ThereIsALinkOfPicAttached