The phrase "scroll button" refers to a small tool on a computer mouse or touchpad that allows you to move up and down on a webpage, document, or other content without having to use the scroll bar.
Sentences with «scroll button»
Left - click, right - click and scroll buttons lie along the top of the touchpad. (laptopmag.com)
(Hint: Click the «select» button behind the menu scroll buttons on the steering wheel, then look in the gauge cluster LCD. (autoweek.com)
The chunky black steering sports two rounded scroll buttons that flank the Tesla logo and horn. (automobilemag.com)