White border around inactive Terminix window

[gregflynn]

Paper GTK Version: 2.1+r265~daily~ubuntu16.04.1
Linux Distro: Debian Testing (stretch) 4.8.0-2-amd64
Gnome-Shell: 3.22.2-1
Terminix: 1.3.0-5

(all of the above are installed from the official repo, except for paper which was manual from snwh.org)

Repro steps:

1. open terminix
2. shift focus to another window
3. what looks like a 1-2px white border should appear around the left, right, and bottom of the window

I specifically mention Terminix because it is the only application i notice this with

[gregflynn]

I've also noticed when Nautilus/Files, Notes, Photos, etc loses focus the window twitches a lot like they're getting the border but then it gets removed, but not other windows that don't seem to be GTK (like chrome, slack, enpass, Atom)

Gnome terminal or gdebi doesn't twitch or get white bars when focus is lost

[gregflynn]

Also tried #414 to see if maybe it was incidentally fixed with the GTK 3.22 fixes for warning but it made no difference

[gregflynn]

Ha and in Terminix if i set the theme variant to dark, it's a black outline but still outside the window. I'll probably poke around in the SCSS more tomorrow

[gregflynn]

I just went and disabled all gnome extensions except for user themes, still occurs. I dug through the source trying to find a :focus { border-width: 0px; } but nothing caught my eye