The Firefox button is orange, or purple when you are in Private Browsing mode. It is not supposed to appear when you are in the Full Screen mode, when you move the cursor to the top of the screen. Only the Tab Bar and the Navigation Bar are supposed to appear in that situation. You need to exit Full Screen mode to view the Titlebar, where the orange Firefox button resides (or view the Menu Bar, if you're not using the Firefox button) and also to view the Bookmarks Toolbar. Two ways to exit Full Screen mode; hit '''F11''' or right-click in a blank spot on one of the Toolbars when you un-hide them with the cursor and select '''Exit Full Screen Mode'''.