How to make navbar items fit the full page width?

Currently all my items stay at a fixed maximum width inside the navbar. When I increase my browser to full screen I would like the items in the navbar to adjust to the full width of the screen. At the current size I can only fit 5 tabs into the navbar like shown. They seem stuck to the width of the section below it?

Select the Navbar in the Overview panel (lower left), go to the Options panel (upper right, middle tab) and click the button that says "Fluid." Your Navbar will now stretch to fill the width of the browser window (as long as it's placed directly in the body, and not a container, etc.)