View > Toolbars > (check) Menu Bar

The Firefox button is supposed to be mutually exclusive to showing title and the title bar and showing the menu bar, but if you have something else on the menu bar that is something they did not plan on. If that is the case the changes are not going to save you space anyway over what you could have done yourself much better.

You can make Firefox 4.0.1 look like Firefox 3.6.17, see numbered items 1-10 in the following topic Fix Firefox 4.0 toolbar user interface, problems (Make Firefox 4.0 look like 3.6)

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.com/kb/Safe+Mode

• https://support.mozilla.com/kb/Troubleshooting+extensions+and+themes

Ok....the safe mode was interesting. When I used that, the firefox button appeared but looked different. It was a rectangle instead of a small circle. Still in safe mode, I added the menu bar and it all worked fine. The firefox button turned into a small circle and the menu bar was completely visible. I don't know what the "extenstions" thing means. But, the fact that it works in safe mode, what does that mean I need to do to fix it in regular mode? Thanks for your help!

Are you using a custom theme or persona (Firefox/Tools > Add-ons > Appearance)?

i wouldn't even know how to customize anything. so, far as I know, it's just a persona. most of those interfere with the text at the top section of the page, so I picked one that was solid.

I didn't do anything to the menu bar! It just started doing that. I didn't add anything "custom" that "they" didn't plan on....I don't know how to do that.