Question: Since Yosemite, the green button in the upper left corner on each window activates the fullscreen mode. By holding the `alt`/`⌥ Option` key, it works as before (Mavericks). Is there any possibility (Terminal?) to change this behaviour back to "normal"? For example: holding `alt` for fullscreen mode?

**Update**

[You can change the behaviour back to "normal" with BetterTouchTool.](https://apple.stackexchange.com/a/157274/41559)

Answer: 
Hold down Option key and click the Green button. It will change from the Full Screen button back to a Zoom button.

You can also double-click the empty area in the window frame (title bar) if you don’t have it set to minimize when double-clicking.

However, this soft can help you : <https://www.macupdate.com/app/mac/30591/right-zoom>

[Apple Support](https://discussions.apple.com/thread/6607235)
Double-clicking the empty area in the window frame (title bar) seems like the best answer. In fact a great one, since this is a larger area than the green button..

Worth noting that Firefox wants to hide the title bar – this threw me for a while. Go to 'toolbars>customize' and click on 'title bar' to get it back.