Sessions and browser's tabs May you have noticed when you open your website in two or more tabs in Firefox, Opera, IE 7.0 or use 'Control+N' in IE 6.0 to open a new window, it is using the same cookie or is passing the same session id, so the another tab is just a copy of the previous tab. What you do in one will affect the another and vice-versa. Even if you open Firefox again, it will use the sa