A brief history of Windows scroll bar shortcuts

For the two decades of Windows, the scroll bar control had just a few basic operations. (For expository purposes, let’s assume that the scroll bar is vertical.) There are five mouse targets: The arrows at the ends of the scroll bar scroll by a line. The regions between the thumb and the arrows scroll by a page. And the thumb itself lets you drag the scroll bar to a specific position.

Windows 7 added a right-click menu to the scroll bar. This menu gave you four options that matched existing mouse operations, two operations that matched existing keyboard operations, and a new operation.