For bugs in Firefox Desktop, the Mozilla Foundation's web browser. For Firefox user interface issues in menus, developer tools, bookmarks, location bar, and preferences. Many Firefox bugs will either be filed here or in the Core product. (more info)
(Windows Only, not sure of the functionality F6 generally provides on other OSes) Make the F6 key, when cycling through the components of the Firefox window, select the Location Bar, and select it before selecting any other component.