I'm using Ubuntu 12.04 and running the Gnome Classic desktop. Whenever I go fullscreen, the taskbars at the top and bottom which hold the menus, notifications, etc. are still visible. This only happens when I'm in a browser or trying to play a game. I've tried it in both Firefox and Chromium, and get the same result no matter which one I use. Videos I watch using VLC however do not have the bars at the top and bottom.
I found only one post about this in the questions, but there were no answers that worked for me. I wasn't sure if commenting my problem into the 5 month old post would move it to the top where it could be seen, so I made this one.