Chat textbox is too small

I don't know if it's the forum software or the Slate theme, but the textbox for chats is two lines tall and there's no way to make it larger. There's a lot of wasted space on the page, and it's hard to draft a message. I guess they expect you to treat it like one-line instant messages or something. It's annoying though.

mine can be maximized..

@Mogonis do you have this at the top? mine did not at the beginning.

The controls don't do anything for the textbox that I can see, whether it's popped out or not.

It's like any other window, go to the edge of it and drag it to the shape you want.

I'm talking about the textbox you type in. Not the window. All you can do is make the textbox wider. It remains two lines tall.