My compatability button is right next to where the web address is typed in...it looks like a piece of typing paper torn in half. After I bring up the chat window, I click that button and enable the compatablity view. In case I'm as confusing to you as I am to myself when I read this...on the top of the window in order it's back button , forward button, web address area, compatablility view button, refresh button, and stop button.
Hope it helps!