Nearly three years ago, I reviewed an early version (1.1b1) of Marc Moini’s Smart Scroll, a utility that let you scroll documents—line-by-line, as opposed to paging up and down—using the keyboard. Since then, Smart Scroll has seen over a dozen updates, and today’s version, Smart Scroll X 2.0 ( ; $19) is a very different—and better—beast.
The current version of Smart Scroll X of course includes the feature I liked so much back in 2004: keyboard scrolling. Especially convenient for laptop users, this feature effectively adds “scroll-up” and “scroll-down” keys to your keyboard. You choose your preferred shortcuts—combinations of the Shift, Control, Option, and Command keys—to scroll up, down, left, and right without having to remove your hands from the keyboard. You can even change keyboard-scrolling speed and acceleration. And if you have a tendency to forget your myriad keyboard shortcuts, Smart Scroll X lets you place a translucent legend somewhere on your screen.

(If you’re also using the excellent MondoMouse, make sure you set up different key combinations for MondoMouse and Smart Scroll X. If you don’t, the results are actually fairly amusing: Your windows will appear to resize on their own.)
But Smart Scroll X now includes two other great features. The first, Super Wheel, is my favorite. Back in August of this year, I wrote about Logitech’s Revolution mice. What makes the Revolution name so appropriate is Logitech’s new scroll wheel: instead of scrolling one increment with each ratchet-click of the wheel, these mice give you “freewheel” scrolling—with one quick flick the scroll wheel, the page scrolls until the free-spinning wheel comes to a stop (or until you stop it manually). Read the original article for more on why this is so great; what’s important here is that Smart Scroll X approximates this behavior in software, so that it works with any mouse—it even enhances trackpad scrolling on newer laptops.

With this feature enabled, giving your mouse’s scroll wheel a quick spin, or quickly sliding your fingers across your trackpad, will result in a “coasting” scroll; it will start out as fast as you would expect, but instead of stopping when you stop (in other words, when you stop spinning the scroll wheel or dragging your fingers across the trackpad), scrolling will continue, gradually slowing down until it “runs out of momentum.” It’s not quite the same as Logitech’s hardware feature, but it’s very similar and works surprisingly well. A handy related feature is the ability to temporarily increase scrolling speed by holding how the modifier key of your choice. (You can also temporarily disable the Super Wheel feature by pressing the Caps Lock key.) One glitch I discovered is that the Super Wheel feature doesn’t seem to work in combination with Kensington’s MouseWorks software.
The other new Smart Scroll X feature is called Grab Scroll and lets you “grab” the contents of any window—text, images, a Web page—and scroll by simply moving the mouse cursor around. If you’ve got a mouse with multiple buttons, you can choose one of those buttons to be your “grab scroll” button; just click that button and then drag the contents of the window around. If you don’t have a multi-button mouse—or if you’ve already used up all of your mouse’s buttons—you can assign this feature to any button with the addition of a keyboard command. For example, on my mouse, I tap Option+Command and then click-drag with the primary mouse button. You can adjust the scrolling speed, and can even opt for a faster scrolling speed when using a modifier key or when “grabbing” near the window’s edge.

Smart Scroll X also offers a few scrolling-related extras. The most unique one is the ability to add scroll-wheel support and live scrolling to FileMaker Pro 6 and 7, and to add live scrolling and proportional scroll-bar thumbs to AppleWorks 5. A minor one that’s also available in a number of Mac OS X tweaking utilities is the ability to choose where window scroll arrows appear: both at the top-left, both at the bottom-right, one at each end of each scroll bar, or—my favorite—both arrows at both ends of each scroll bar.
Unfortunately, Smart Scroll X doesn’t work in all applications; for example, I couldn’t get it to work at all in Camino, and the Super Wheel feature didn’t work in the Finder for me. And you have to be careful with your choice of keyboard shortcuts; for example, Microsoft Word and Excel 2004 use Control+scroll as a shortcut for document zooming, so if you use the Control key as a scrolling shortcut in Smart Scroll X, that shortcut will end up zooming your Office documents. Finally, note that Smart Scroll X uses Unsanity’s Application Enhancer system. Some people refuse to use “haxies” on their system and thus won’t use Application-Enhancer-based products. I personally use several such add-ons with no ill effects, but I include this information for those who care. (On a related note, if you find that Smart Scroll X conflicts with a particular application, you can add that application to the Exclusion List in the Application Enhancer pane of System Preferences.)
Smart Scroll X won’t be for everyone, especially if you’re already using certain third-party mouse drivers or scrolling software. But I find its Super Wheel feature alone to be worth the price of admission.
Smart Scroll X requires Mac OS X 10.3.9 or later and is a Universal Binary. A utility, Rosetta TuneUp.app, is included to prevent crashes with non-Universal applications on Intel Macs; however, I didn’t experience any Rosetta-related problems in my testing, so I didn’t need to use this utility.