I have been using firefox in windows for a long time. I like pressing the backspace when I want to go back in the browser. I have switched to Linux and noticed that the default behavior for the back space and shift backspace is a page up and page down. I found a way to fix this issue from this sie here.
I will tell you how it is done encase the link doesn't work. In fire fox type about:config in the url address bar. Then find the preference name: "browser.backspace_action". Change its value to 0 to chage the default behavior of the backspace to really go back in the browser. Then shift backspace will go forword also. I really like this fix. Leave comments if you liked this article.