How do I make the backspace key not go back to the last page in Opera?

It's really annoying when I have to backspace something and It goes back to the last page, how do i change the keyboard shortcut so that backspace doesn't do that anymore?How do I make the backspace key not go back to the last page in Opera?
Key Customizer is a software which can change any key on the keyboard into other keys or disable your keys you dislike. But Key Customizer is not just a tool that allow you to customize your keyboard layout. With it, you can change your common 102 keyboard into a multifunctional one without costing much money. Want the N key to press Ctrl+V? Want the pause key to type frequently used text such as email address? Want F9 key to turned up the volume? What F12 to close the DVD driver? Want to lock the keyboard? Key Customizer can do these easily, it could help you make good use of each key on the keyboard.How do I make the backspace key not go back to the last page in Opera?
Key customizer helps you do that.

when i am playing game,i have my habit in keyboard.at last i got key customizer,which makes it more fun to play game!!

http://www.keycustomizer.com