I'm new to the forum guys, please cut me some slack!

[imghttps://i.imgur.com/DCD3w7u.png[/img]
In the image, it shows that unmaximised windows have a black border around them, but only for the Breeze Window Decorations. I think it might have to do with Emerald, I'm not sure. Is it a problem with Emerald, or is Breeze Window Decoration broken, or is it something else altogether?