This region demonstrates a button bar that can be used to navigate between widgets, and also display menu buttons.
This region also has a custom style applied to the button container. You can style these "button containers" relatively easily by adding some custom CSS to the page.
For example, the class button-bar has been applied to the region in Page Designer, and the following CSS has been added to the page:
.button-bar .t-Region-buttons.t-Region-buttons--top {
border-bottom: 1px solid rgba(0,0,0,.1);
background-color: rgba(0,0,0,.05);
}