Apple Mac OS X Lion

With Lion, Apple has combined all of these features into a single interface called Mission Control. When you activate Mission Control by clicking on the Mission Control app in the Dock, pressing a keyboard shortcut (F9 by default), or gesturing (swiping three or four fingers upward), you see an Exposé-style view of all the currently running applications with thumbnail views of all their open windows. At the top of the screen, there's a list of all available spaces--including not just the virtual desktops that the old Spaces feature offered, but also all apps running in full-screen mode and (by default) Dashboard.

Configuring those spaces is simpler now: If you want to stick an app or a window into a new space, you drag its icon or window towards the top of the Mission Control screen. As you drag, the image of a new desktop appears in the corner of the screen, with a helpful plus icon. Drop the icon or window on that image and a new desktop space is added to the array at the top of the screen. You can drag items from space to space, but can't rearrange the order of spaces.

Though you can move between spaces via keyboard shortcuts and clicking, it's best handled via a trackpad gesture. A three-fingered swipe left or right on the trackpad will take you from space to space. It feels natural; I'm more likely to use Dashboard now that it's just another space. Fans of the previous Spaces will need to re-orient; the old way allowed you to create a two-dimensional grid of spaces, but Mission Control limits you to a single horizontal strip. However, working with those spaces can be disorienting: When you switch between spaces, the order of desktops can get mixed up; items that were floating on top can end up behind another window. There's definitely some fine-tuning to be done here.

I like the visual, tactile approach Apple has taken with Mission Control. I'm not sure if novice users will ever take to organizing windows and apps on multiple desktops. But since every full-screen app gets its own space by default, many people will end up using Mission Control whether they want to (or know they are) or not. I also wish there was a way to manually re-order spaces. Still, while Spaces had its adherents, I think Mission Control will be embraced by many more Mac users. By bringing Exposé, Spaces, and Dashboard together into a more unified whole, Mission Control is greater than the sum of its parts.

Full-screen apps

Lion adds a new capability that any app can take advantage of: the ability to run in full-screen mode. Once an app is updated by its developer to support this mode, a double-headed arrow icon appears in the top-right corner of the app window. Click on it and a couple of things happen.

First, of course, the app slides into full-screen mode: You see nothing but that app; no other windows share the screen. Also, the menu bar and Dock disappear. (Really, they're just hidden; if you nudge your mouse to the edge of the screen they will reappear temporarily). And the app becomes a space unto itself in Mission Control. To exit full-screen mode, you move your cursor to the top of the screen and, when the menu bar reappears, you click on the blue double-headed arrow in the top-right corner.

This is an interface approach that Apple has been heading toward for a while: The existing versions of iPhoto, iMovie, and GarageBand all want to be run in single windows, as large as possible. With Lion, more Apple apps join that party, including Safari, Mail, and iCal. Presumably, many third-party apps will follow.

It's interesting that Apple has decided to take this approach. On the one hand, it's another way that Mac OS X now mimics iOS. But on the other, it's also a throwback: One of the first things I noticed way back when I first compared the Mac with PCs running Windows was that Windows took a monolithic approach to apps: They were largely meant to run maximized, with one giant window taking up the full screen. That was very different from the Mac, which had an interface full of small, interrelated windows. Now, here we are in 2011, and Apple has seemingly embraced that monolithic approach, at least in some cases.

Lion's full-screen mode can't be judged on its own. Instead, we need to judge the way each app uses it. Some apps, such as iCal, iTunes and GarageBand, are essentially one giant window, so they're tailor-made for full-screen. Mail's wide, multi-paned approach fits well, too. On a small display like an 11-inch MacBook Air, full-screen mode is especially helpful in eking out a little extra space.

Full-screen mode is less successful in other Apple apps. Safari especially feels like a failure: Most web pages just don't need to be as wide as your screen; they're designed at fixed widths, and nobody wants to read super-wide lines of text anyway. Sure, Safari has the new Reading List pane to fill up space on the side, and it could find other things to put over there (bookmarks, history). But I still don't see the appeal of forcing my web browser to take up 100 percent of the screen, even on a MacBook Air.

If app developers come up with good uses of all that extra space, full-screen mode could be great. For example, one of my favorite apps, the long-form writing tool Scrivener, has a multi-paned interface that could be perfect in full-screen mode. There's a writing section in the center, with controls at the top, a binder full of different sections on the left, and (optionally) an inspector pane with more detail on the right. It could usefully take advantage of the full screen.

But if vendors just make their existing apps as wide and as tall as possible, full-screen mode won't be that useful. One third-party Twitter client app I tested had enabled full-screen mode on an experimental basis, but all that happened was that individual tweets appeared at full-screen width. That sort of approach will probably be common, but it's a waste of time. In most cases, app developers will need to give some serious thought to how best to use full-screen mode, or the feature could become a largely unused gimmick, kind of like Dashboard.

Note that full-screen mode has apparently been designed for Macs with just one display. On a two-monitor setup, one display shows the app, the other shows nothing but the newly ubiquitous linen background texture. It's a waste. I'd much rather have two apps running in full-screen mode, one on each display, or even have one app in full-screen mode while the other screen is displaying one of my regular desktops. Until Apple addresses this issue, I can't really recommend full-screen mode for anyone who relies on multiple displays.