That's the Bookmarks Toolbar. When you bookmark a page, you can put it there instead of the Bookmarks Menu. More info in this article: [[Bookmarks Toolbar - Display your favorite websites at the top of the Firefox window]]. BUT... about "undeleting" something. Try opening the Library dialog using either: * Ctrl+Shift+b * Bookmarks menu > Show All Bookmarks If you click the Organize button, the Undo option might be available. As with Undo in other contexts, it undoes changes in reverse order, so if the deletion took place a while ago, you might lose changes you actually want to keep. It's really only useful immediately after the change you want to undo. ---- Firefox creates regular backups of your bookmarks, so if you lost the bookmark not that long ago, you might be able to get it from a backup. That's more complicated than I made it sound, so let me know if you want the details.