Follow macOS UI window control defaults

[deviantintegral]

Look at these three windows. Normally, this would mean some window outside of the screenshot has focus. However, the top Zen window is actually the topmost window.

This gets especially confusing when you have multiple Zen windows open over multiple monitors, and you're not sure what is in focus.

This appears to be an intentional decision, but one that is very confusing and unique to Zen. I've never seen another app behave this way.

#9315
#9871
#6036
#6067
#6776

Luckily there's an advanced preference for this at zen.widget.mac.mono-window-controls, but one shouldn't have to splunk through there to get an app to match default system behaviour.