If I want to register a bookmark, with the last releases of Firefox, I select (Italian version) Segnalibri/Aggiungi pagina ai segnalibri (Bookmarks/Add a page - I think, in the English version). Once this choice opened the window from which to choose the folder where to save the bookmark. Now, instead, the bookmark is saved, without asking for anything. To place it in the folder of interest, you need to select again Segnalibri (Bookmarks) and the the option Modifica segnalibro (Modify bookmark). It's an useless time consuming process.