My assumption was that I get a folder "Nix" in the bookmarks toolbar that contains the four bookmarks. But instead the four bookmarks are added to the toolbar side-by-side without being in a folder.
If you open the bookmarks utility in firefox, does it show as a folder as expected? I think maybe toolbar should be false if you expect to see your folder on the toolbar
Thanks for the reply. When I disable the toolbar, the bookmarks are correctly placed in a folder but the folder is not visible in the toolbar anymore. So I can either have the bookmarks separately in the toolbar, or in a folder but not in the toolbar. The combination of both seems to be only possible if I move the bookmarks by hand in the UI :/