In the upper left hand corner of nearly every app window on a Mac there are three buttons. Red, yellow, green. Not one of the three buttons has a pop up window describing what the button does so you move into trial and error mode. Click the red button and the app window closes. Most of the time only the window, but some apps also close (System Preferences, for example).
Click the yellow button in the middle and the app window swooshes with special effects and then minimizes into the Dock, off the Mac’s screen, out of the way. What about the green button? That’s a different animal and seldom seems to work the way Mac users expect.
For smaller app windows, click the green button and the window enlarges downward (but not full screen). Click the green button again and the window reverts to the original size. What most of us expect the green button to do is simply to make the app window take up the Mac’s entire screen (but not Dock or Menubar). It doesn’t do that.
Add Right Zoom to your Mac and you’ll get the behavior you want for free. Click the green button and the app’s window will expand vertically and horizontally to maximize the window in the available screen space.
Configurations are straightforward, too. Select a hotkey to maximize windows if you don’t want to click the green button. Or, set it to maximize only when a specific key is clicked. Right Zoom is smart enough not to affect iTunes, where the green button minimizes iTunes’ controls. You can also create a blacklist of apps where Right Zoom does not change the green button’s behavior.
Nicely done, useful, and free.