What I see now is the Problem it occurs to me to. The Fontsize is very big.
The easiest way is to install that nUI Plugin with the GUI Configtool:
http://www.wowinterface.com/download...ChatFrame.html
or you use Prat-3.0 and then change the Font and the Fontsize over Prat
I use both, because Prat doesn't work correctly in current Version, because it is not full compatible at the Moment. The PTR Version is already and if the next Patch is coming, it'll work. At the Moment you should use the config Tool for nUI for Font and Font size and disable in Prat everything have to do with Chatframe movement, ability and Editbox chaning.
If you only will use Prat, then you have to search in the Forum, somewhere standing what to change that Prat is correct working. Therefore you have to change some code in the lua-files. Be carefully with that if you doesn't know what you are doing and wait for the next patch.