Interesting configuration…
This is a case where what you want to do is not extend the header widget area container full width, as that goes over the wrapper’s border, so remove the wvrx-full-width class
What you want is use XTreme Full Width BG feature on it.
As the header widget area does not have the Full width BG box options, you need to use the custom CSS provided by weaver below with a few additions
http://forum.weavertheme.com/discussion/9712/extending-bg-to-full-browser-width#latest
.is-desktop #header-widget-area {
position: relative;
overflow:visible;
}
.is-desktop #header-widget-area:before {
content: “”;
position: absolute;
top: 0;
bottom: 0;
left: -9999px;
right: 0;
border-left: 9999px solid #595A5B;
box-shadow: 9999px 0 0 #595A5B;
z-index:-1;
}
.is-desktop #branding {z-index:auto;}