I noticed that too ... It basically made your screen a HUGE widescreen and the poker was on the left side. I hid it manually by just moving it out of the way. The only way to remove it would be to Uninstall the program, and INSTALL Americas Card Room
Simple answer: you can't. I always see people saying that it goes away if you play however many tables at once, but I have never tried it. I think it's four tables.