When I added some tags that I used to organize my bookmarks to the bookmarks bar, I noticed that the bookmarks within the tag are not alphabetized, although the order is clearly not compltely random either, see screenshot. For example, both 'Antipode' and 'ACME' are not where they should be in an alphabetical list, although the rest of the bookmarks appear to be in alphabetical order.

I wonder how Firefox orders bookmarks within a tag and if there is some way to change this order (alphabetize them).