On MDN, the phrase "Add-on Manager-enabled XUL" is introduced. By dragging a XPI file containing an add-on and dropping it onto a FireFox window, the addon's widgets will be installed in FireFox's add-on bar. By specifying the commandline option "-app application.ini" at the root of a chrome-structured directory, Firefox will display XUL using chrome:// protocol. Since MDN makes me think that the two are not mutually exclusive, my question is, "What do I have to do to get Firefox 8.0.1 to display the add-on bar and XUL simultaneously?"