Can't use anything...

So I'm not sure if this is just me but everyone once and a while, I go into a game and can't use any skills, summoners, etc. This isn't because I have a screwed up keyboard because if I leave the game then join back in, the game goes back to normal. It's weird though because I can use the skills if I actually click on the icon in game but I just can't press a key to get them to work.