How can I start Private Browsing when I do not have a "Firefox button" to click?

"Open a new, blank Private Window

   At the top of the Firefox window, click the Firefox button and select New Private Window. A new Private Window will open.


That is what it says! But where is this Firefox button at the top of my Firefox (v 20.0.1) window? What I have at the top of the window is:

(1) A blue-background bar with the Firefox icon and the title of the current page

(2) 2 grey-background bars with menus (e.g. File, Edit, ...) and buttons

(3) 1 grey-background bar with the Bookmark Toolbar

(4) The Tab bar

                                 But no Firefox button, and none available in the customise dialog. Have I suppressed it somehow?
↓ Show more ↑ Show less
  • All posts
  • Helpful Solutions
  • post
  • solution
  • owner