You might already have worked this out, but just in case... Once you have selected the category (Bookmarks Menu, Bookmarks Toolbar) in the left column of the Library dialog, you can create a new folder on the right side by using either: * right-click a blank area or existing bookmark > New Folder * Organize button (on the toolbar) > New Folder If your toolbar doesn't display captions, just icons, the Organize icon is the one that looks like a stack of paper.