I’d also like to draw your attention about the UX of the max/min/close buttons. The issue with ambiance is that the click area is wayy to small, making it hard to hit it. You don’t notice this until you’ve used Adwaita or other OS’s for a while.
One of the ways to solve this is with a theme like Nautilus_V22Nov17_A - higher contrast
Here, you can make the entire area around the X clickable, not just a small circle. If the user clicks in the upper right corner of the window, the window will close, even if he doesn’t click right on the x. The size of the click area should be made clear when the mouse hovers over it, however.