Sometimes it zooms, sometimes it maximizes and sometimes it just does wacky stuff that no one can really explain. The green button in all OS X windows has been a nuisance since the public betas and it’s (long past) time Apple fixed it.
A Brief History
Actually called the zoom button, it dates back prior to OS X (at least as far back as System 6) and was one of only two buttons in the Macintosh windowing interface (the other being the close button). Back in those days, the zoom button actually did what it was supposed to do: enlarge or shrink the window to the minimum height and width necessary to fit the graphical content. A second click on the button would return the window to its previous state, essentially working as an Undo.
A user could always drag the right-hand corner of a window to resize it, but that is an imprecise action with a mouse and one that is essentially unnecessary since the computer knows the exact coordinates to size the window to eliminate the need for scrollbars. Once you added or removed files to a folder, you could click the Zoom button to quickly resize it to its most efficient size. In an operating system designed for dragging and dropping files from one window to another, this was incredibly useful.
That usefulness continued throughout the years as the zoom button kept its place in the interface through all the iterations of the Classic MacOS (7-9) and it even gained the ability to maximize windows (option-clicking the zoom button).
Where Things Went Wrong
The intent of the zoom button was brought to OS X in the green button even in the beta versions. Unfortunately, its effect was not so easily ported. Finder windows seemed to be blind to the Dock in early versions of OS X. Clicking the green button would enlarge the window so that it touched the bottom of the screen, leaving the bottom-right resize corner underneath the Dock.
This was compounded by the Finder’s seeming inability to remember window sizes. Even on the rare case that the green button resized the window correctly and there were no visible scrollbars, on reopening the same window a scrollbar would appear on one or both sides.
Even today, in version 10.4.9, the Finder still has problems correctly sizing even simple folders with less than 10 items in list view. To make matters worse, a second click rarely works as an Undo. Instead it picks a new size, often worse than the last one.
For instance, I have my Applications folder set to Icon view, Keep Arranged by Name and three columns wide. If I click the green button, what should happen? It should grow the window vertically to the top of the screen and the bottom of the screen (above the Dock) to accommodate the 100+ icons and shrink the window horizontally to fit exactly the three columns currently showing. What does it do instead? It shrinks the window horizontally so only two columns of icons are showing but leaving nearly a full column of empty space on the right. Oops, let me hit the zoom button again. Now it’s shrunk the window again so there’s only one column of icons but nearly a full column of empty space. Why not click it again and see what happens. Now it has shrunk the window horizontally so much that there’s a scrollbar at the bottom. One more time? Now it has extended the window vertically so it extends beyond the bottom of the screen and the resize handle is completely inaccessible (see this screenshot). The only way to fix the window’s size is to turn off the toolbar and press the green button. Gee, that was intuitive.
Of course, the list of weird Finder behavior could fill a book (a poor-selling and depressing one, but a book, nonetheless). But the Finder isn’t the only application where the green button acts abnormally. In Preview, when viewing an image smaller than full-screen, it will expand the window, but not to full-screen. And it won’t enlarge the image, so it just half-fills your screen with a bunch of gray border area.
In Safari, where the button should expand the window horizontally to accommodate the length of the active web page, sometimes it moves the entire window so the titlebar is in the middle of the screen and the status bar is below the bottom and inaccessible. Sometimes it moves the window to the right just one or two pixels, and you can slightly see the windows behind the browser on the left. I’m at a loss to what the point of that could be.
This bizarre and useless behavior of one of OS X’s longest-running interface controls is simply unacceptable. Longtime Mac users are left frustrated by something that worked so easily and consistently on older, inferior versions of the Mac.
The green button is not a maximize button
Windows users probably find the green button even more frustrating because they’re familiar with the longtime three-button Windows controls of close, minimize and maximize. Since OS X windows also have three buttons (just on the opposite side of the titlebar) and two of them are close and minimize, you can’t really fault them for expecting the green one (which shows a + symbol when moused over) to be a maximize button. It’s not uncommon to see a new Mac user mention the lack of a maximize button on a blog or as feedback to a ‘Switch to the Mac’ article.
Except when it is
Further confusing matters for these users is that in some applications the green button does maximize the window to full screen. Applications such as iMovie, iPhoto, iCal and GarageBand, for instance, will expand their single-window interfaces to the entire screen when the green button is clicked. As will Utilities such as Activity Monitor, Disk Utility, Network Utility and System Profiler. Even blank windows in Dictionary, TextEdit and Terminal will expand to full screen when the green button is clicked.
Then there’s iTunes
And then there’s iTunes, where clicking the green button of the main window actually shrinks it to a mini-player. This command is (ironically) called Zoom in the Window menu. iTunes also has the distinction of being one of the few (only?) applications to have a keyboard shortcut for the green button: Control-Command-Z.
Who can blame Windows users for being confused when the Windows version of iTunes—probably the most well-used Apple application for Windows—has a full-screen maximize button and the OS X version doesn’t? The other major Apple application on Windows, QuickTime Player, also has a maximize button.
What to do
First, the Finder’s zoom button must be fixed. It should behave consistently and be useful. Is it the only problem with the Finder? Certainly not. But after six years and three paid upgrades to OS X, it’s an issue that still lingers unnecessarily. Different applications assign different behavior to the green button, but Apple can’t blame anyone else for how it works in their applications, which make up a larger percent of the OS than ever before.
Second, iTunes needs to change its behavior. The green button should not turn iTunes main window into a mini-player. It should follow the example of its iLife brethren and maximize the main window as much as necessary vertically to show all the playlists and as much as necessary horizontally to show all the metadata columns. The mini-player functionality can still be invoked via the Window menu and the keyboard shortcut. And if a visual control is necessary, create a distinct interface icon. As one of Apple’s most important applications, and one most likely used by Windows switchers, it should be setting an example for best behavior, not weirdest.
Maximize vs. Zoom
I realize that many former/current Windows users would prefer the green button maximize the window when clicked and many longtime Mac users would prefer the green button zoom the window as it sorta does now. So how do you solve an issue where one person wants the behavior one way and another wants the behavior to do something different? Preferences. OS X already has preferences that deal with Windows/Mac differences. The “Automatically log in as” and “Always open folders in a new window” preferences makes OS X a little more like Classic Macs. And the “Show all file extensions” is probably valued by many Windows switchers. More importantly, users can choose what they prefer, be happy and not go griping on blogs about X Things They Hate About Using OS X.
The zoom button used to be useful and reliable, Apple. Make it that way again.