When you bookmark (bm) a single tab firefox remembers the location you last bookmarked so if you then bm another tab it will default to saving it in the same location as the last location you chose to bm (with the option of choosing a different location of course)
However when bookmarking multiple tabs (grouped as a new bm folder) if you choose a location firefox will not remember this choice. It only remembers last-bookmarked-locations of single tab bookmarkings. So if I want to continually bm multiple tab folders in some location I have to make sure I save a single tab there first so as to activate firefox defaulting to that location which often turns into me dummy bming something just to "load its location in as the current default location"
I don't know if this is a feature or an oversight, but it's incredibly annoying and bad design in my opinion. A fix is relatively quick and easy.
