What were you doing previously? If you were previously displaying the toolbar list and unchecking the Navigation Toolbar to hide that entire toolbar, that hasn't been allowed since Firefox 29. If you are looking for a feature like that, you could investigate the Classic Theme Restorer extension, which is like a time machine to roll back various different changes in Firefox. See: https://addons.mozilla.org/firefox/addon/classicthemerestorer/ If you meant hiding the address section of the bar more selectively, there might be some other add-on or custom style solution (it's not a built-in feature).