I, Robert

Gruber Correction: Scrolling in Lion

On the latest episode of The Talk Show (#52), John Gruber notes the change in metaphor for window-scrolling behavior between Lion and all previous versions of Mac OS. This is described (inaccurately) as the difference as being between moving the “thumb” of the scrollbar and moving the window viewport. In fact, moving the viewport is the same as moving the thumb. Scroll the thumb down and the viewport moves down the document, like you’re looking at your page through a window that can move around like a spyglass.

In Lion, instead of moving the viewport, you move the page itself. Your viewport stays where it is, and your fingers scrolling are pulling the page up into your view. That’s a significant change in metaphor that removes a level of abstraction from the UI by switching your control from the window to the content of the window.