You have a Birthdate field on a form. When trying to select the year, you notice it only shows 20 years at once. When first clicking, it shows the current year, then 10 years ahead and 10 years behind. In order to see previous years, you must select a past date, then the reselect. There is not an option to scroll.
By default only 20 years show at a time. If the user wants to select a year that doesn't show right away, they must select a past year, then reselect the year.