have you tried the "Add Bookmarks Here" add-on?
S.
It would help to know where you are looking. Shortcuts shown here
assume you are on Windows.
* autocomplete list at the location bar ("awesomebar")
* bookmarks menu
* bookmarks sidebar (Ctrl+B)
* bookmarks Library list (Ctrl+Shift+B)
In the library list you sort a column by clicking on the column header
for {ascending | descending | unsorted }
by clicking, clicking again, or again to not sort (or use the View menu there).
You will have to do that each time though.
To permanently see a sorted arrangement (doesn't actually affect the
database) you should use the "SortPlaces" extension.
https://addons.mozilla.org/firefox/addon/9275/
For more information besides the extension and the author's home page, see
http://kb.mozillazine.org/Sorting_and_rearranging_bookmarks_-_Firefox
http://www.mvps.org/dmcritchie/firefox/firefox.htm#sortplaces
The "Add Bookmark Here ^2" extension is a must have, but is not the
solution to this problem (4 minutes from question to first answer is
remarkable, I would guess somebody's clock is off). I would also recommend
the "Stay Open Menu" as another unrelated extension that would help
with bookmarks (in menus).
--
HTH,
David McRitchie, extensions I use are briefly documented on my site
Firefox Custom: http://www.mvps.org/dmcritchie/firefox/firefox.htm