One of the new features in OS X Yosemite is a re-working of the full-screen window feature where in programs that support this option, the green zoom window button now defaults to being a toggle for full-screen. This can be seen in programs like Pages, and Preview; however, this can be a bit confusing because in those like TextEdit where a fullscreen option is not available, the green button is the classic “Zoom” behavior that resizes a window to fit its contents.
Unfortunately for now there is no way to disable this feature, at least without modifying core files in specific applications, so the confusion may persist, especially for those who have regularly used the Zoom feature in specific applications. For example, in Preview or other image editors, zooming will resize a window to match an image perfectly, where for this purpose the new fullscreen option for the Zoom window may be less desired. In these cases, there is an approach you can take to invoke the old Zoom functions every time.
Holding the Option key on your keyboard will have this double-arrow change to the classic plus symbol, indicating the zoom resizing feature will be used, instead of invoking full-screen mode for the window. To ensure this always happens, simply hold down the Option key whenever using this button.
Thanks, I needed that. In an app that does not support the new zoom function, will the Option key make any difference in the zoom behavior? I think this is an important distinction because, as you suggest, there’s no simple way to know which behavior a given application supports.
You can also Just double click an empty space in the window bar. I find this much easier than holding the option key.
I should say Double TAP, as there is a difference.