I just upgraded to Ubuntu 18.04. In my previous version, the title, status, and the "File ..." menu were all bundled together in a neat little bar for every maximized window.
Now they are all separate, and as you can see they are taking up a huge amount of screen real estate. Is there any way to get some of it back?
2 big bars
3 big bars
Assuming this issue is only on Firefox, go to the browser's menu and click Customize. At the bottom, there is a dropdown menu called Toolbars. Your menu bar will be selected. Deselect it.