Customize Firefox controls, buttons and toolbars {web link}

Type about:customizing<enter> in the address box.

Note: about:customizing is no longer present in Firefox v47+ releases.

• Press Alt or F10 to bring up the Menu Bar. Then View > Toolbars >
• Right-click on a blank spot on the toolbar and select what you want.
• Right-click on a blank spot on the toolbar and select Customize Toolbar.
  Look for Show / Hide Toolbars or just Toolbars at the bottom left.
  There is also a Restore Defaults button at the bottom right.

Make sure you do not run Firefox in Full Screen Mode (press F11 or Fn + F11 to toggle; Mac: Command+Shift+F).

• https://support.mozilla.org/en-US/kb/how-make-firefox-and-websites-go-full-screen

When you are in Full Screen Mode, hover the mouse to the top of the screen to make the Navigation Toolbar and Tab bar appear. You can use one of these to leave Full Screen Mode:

• press the F11 key
• click the Maximize button at the right end of the Tab bar
• click the Full Screen button in the "3-bar" Firefox menu button drop-down list
• right-click empty space on a toolbar and click "Exit Full Screen Mode"