"use keystrokes to scroll on alternate screen" is an option in gnome-terminal profile preferences. It seems that the person who wrote the help doesn't know either because he skipped that option in the gnome-terminal manual. What is going on? That happens at least in Ubuntu-Natty, but I doubt they have fixed that.
Answer: Hahaha.. It should be "enable the use of mouse scroll on alternate screen (an alternate screen is a screen superimposed when you read man pages for example)" and not “use keystrokes to scroll on alternate screen” . Hahaha. the meaning is the opposite. What is going on with quality control in UBuntu? They are ruining the prestige of Linux.
Who will correct that??