Yeah there really is no way to get windows back to normal size. On third party apps and browsers. For me double clicking where the fullscreen button was in Safari works for both maximizing and resuming to normal size.
I also noticed when Safari is not at the very top of your screen (touching your menu bar) double clicking where the fullscreen button used to be will put it back up there.
I personally never use the green button in Safari because browsing the internet on a 27 inch iMac in fullscreen looks as if it will blind me
When you double click where the fullscreen button used to be it messes it up so don't use that method unless you want that app to run in larger resolution or you want to waste time dragging it back to the normal size when using your third party internet browser.
----------
Can you clarify what you are saying here^
I'm trying to figure out if you are saying the green button is not showing up in Safari in fullscreen. You are saying it disappears right?
Answer to that question is you have to move your mouse pointer up to the menu bar to get the green button back when in fullscreen to return back to the normal size window.
Then you say you right clicked next to the arrow keys which I believe would get you to the customize toolbar page and allow you to add buttons. On my Safari I do not see the option to add the Green Button or the Fullscreen button. Are you saying that you do see these options in your Customize Toolbar screen? If so can you screenshot it?
Here is what mine looks like:
Image
