Help direly needed

I accidentally enlargened my chatbar to the point where it covers 1/4 of the screen, how do I turn it back? It's unbearable..

While in a game click near the border like your dragging a application across your screen. You can change its size this way.

Type /reset

Thanks to everyone. Though the dragging method is a bitch because it's very hard to pinpoint the point from where you can drag