What is the user experience reason for maximizing only the height of a window in Mac OS applications? The green "+" button only maximizes the height in most programs, with no change to the width. Is this really a better user experience?

Mac program control buttons

The "-" and "x" buttons work as I would expect. I end up resorting to third-party tools to make snapping and maximizing windows easier (one of the few UI things that, in my opinion, Windows got right). What gives?

  • Just wondering: which third-party tools do you use for this? Commented Apr 6, 2014 at 9:35
  • @DanielGibbs I use Cinch, but there may be others.
    – Vortico
    Commented Apr 6, 2014 at 13:51
  • @DanielGibbs BetterSnapTool. It's slightly glitchy with multiple monitors sometimes but for the most part works pretty well.
    – Matt
    Commented Apr 6, 2014 at 13:53
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    To add some history, MacOS never had 'maximized' application windows. It was always a multi-windowed UI unlike Windows, which did have fully maximized app window concept.
    – DA01
    Commented Apr 7, 2014 at 7:42
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    press the green button while holding shift-opt, it should do the trick.
    – guenis
    Commented Oct 24, 2016 at 9:29

2 Answers 2


Update: In Mac OS X 10.10 Yosemite and later, it seems the zoom button has been replaced by the fullscreen button. The green widget no longer contains a plus sign, but two outward-pointing arrows, and places the window in fullscreen mode. To zoom a window, you now option-click this button.

Yosemite's three window widgets, close, collapse and fullscreen

The green button isn't for maximizing. If you want to maximize, use the "fullscreen" button in the upper right of the window:

Fullscreen button on a window

The zoom button is intended to make the window the best possible size that shows the most of the window's content. This is the most useful when working with multiple windows, because you see as much as your screen will hold, but it still leaves enough room in which you can position other windows. (E.g. I often have a Twitter client or chat program open on the right hand side next to the browser)

This feature is especially useful in very old (like the Finder in System 7) or very new applications (i.e. ones that support state restoration) because those will reliably remember the previous position where you put a window. So when you restart your Mac, your Safari window will open beside the chat window, and your setup will be just the way you left it.

Many applications written in the interval between those two eras will just open a window in the upper left, then keep stacking new windows down and to the right, overlapping that window, and give it a default size. That, of course, defeats the advantage of a reliable position for multiple windows to let you arrange your windows onscreen to optimally fit your content.

For comparison, imagine your desk: you can place sheets of paper on it, all have different sizes, maybe different colors, and they can overlap. Since the human mind is optimized for the physical world, you can jog your memory about which sheet it is, just by seeing the corner or an edge (and thus a hint at its size), its thickness and maybe its color, and a hint of whatever's written on it.

Applications that don't remember the position are like when Mrs. Hudson goes through Sherlock Holmes's apartment every morning, dusting off everything and neatly stacking stuff. It is no longer in the position he remembers from last night, and as they're all stacked on top of each other, you can't see it peek out to judge its size, color or content either. Zooming is optimized to support that workflow, make window sizes more unique.

The problem with web browsers is that they use one window for different content, and don't remember window sizes. Thus, the only way to use them without going mad is to make them the size of the screen. Otherwise you'd have to manually resize them every time.

  • 11
    The fullscreen button wasn’t there 5 years ago. Apple had no excuse for such behavior of the + button back then.
    – kinokijuf
    Commented Apr 6, 2014 at 15:37
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    @kinokijuf How so? As Uli points out, the point was to allow you to see multiple windows from multiple apps at the same time (which isn't possible on Windows when the system maximizes the current app), and to use spatial memory to be able to quickly and easily get at them regardless of which one is currently on top. It's a very good excuse in my opinion. Commented Apr 6, 2014 at 16:14
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    @user1118321 my point is that there was no real way to maximise back then
    – kinokijuf
    Commented Apr 6, 2014 at 16:40
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    Before the fullscreen button was there, you could click the zoom button with the option key held down to make a window fill the screen.
    – uliwitness
    Commented Apr 7, 2014 at 7:44
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    It's the fact that Apple added extra buttons to the title bar in OS X that was a mistake. In classic Mac OS we were perfectly happy with a close button and a zoom button and that was your lot ;-)
    – nekomatic
    Commented Apr 7, 2014 at 10:55

The window expands to fit the content, and don't add additional whitespace like windows OS does.

Now let’s look at Apple’s website in Safari. Notice the first image below is a very small window with both vertical and horizontal scrollbars. The second image shows what the window looks like after clicking the Zoom button. Again, it takes up all of the vertical space because there was more scrollable content to be seen. The third image illustrates what the screen would look like fully maximized Windows-style.

enter image description here


  • 11
    From the reference - "Try web pages with a different width and it will size the window differently each time, depending on what’s on screen." It seems pretty frustrating to have to re-maximize when clicking to a new page. Commented Apr 6, 2014 at 9:44
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    @mikel Agree to that. But you don't have to resize the window using the button or keyboard shortcuts. You can do it manually :-) Commented Apr 6, 2014 at 9:49
  • @BennySkogberg, what is "manually"? should i physically grab the window borders and try and stretch it with my fingers? Commented Apr 6, 2014 at 13:15
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    Interesting! I guess apps have to support that kind of viewport sizing then. In my opinion, though, zooming the window to full the screen would be a bigger win than not having extra whitespace. Maybe it's just a matter of preference.
    – Matt
    Commented Apr 6, 2014 at 13:57
  • This seems very much like what Android phones do (maybe others) when you double-tap the screen. The screen becomes as wide as the block of content you double-tapped. Of course, almost all apps are always full-screen, so you're zooming in, not making the window bigger. Still, I wonder if this was inspired by OS X?
    – trysis
    Commented Apr 6, 2014 at 17:17

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