I have a MacBook Pro and ever since updating to Mountain Lion, I've been having this problem with Safari. First of all, after being on it for a while, the "x" that lets you close tabs simply disappears, and I have to close tabs by right clicking them. Second, everytime I try to shut down my Mac, it says that Safari is not letting it shut down and I ALWAYS, ALWAYS have to force quit it. This can't be right and it's annoying!!!!!! Someone help!!!