Bug very annoying that prevents me from playing correctly

When the game launches, the screen doesn't get full with the game: there is like a white bar in the top that is said Leagueoflegends-client. I can also move the kind of window in my screen. The real problem is that i can't scroll down, but only down: top, right and left works perfectly. It might not seem a too big problem, but not scrolling down makes ganks so hard on blue side and when i'm on red side i just can't lane.

Did anyone get the same problem as I do, or have any solution...

PS: I had this problem in the beta, but also in the normal client. I tried changing my settings, uninstall- reinstall, and it doesnt work, so I have really no idea of how to deal with this problem