When a new sub group is created, it should be sorted-in alphabetically

[koppor]

We do have "Sort":

In case the group sub tree is sorted alphabetically, a new group should be added alphabetically (and not be added to the end)

[koppor]

Instead of checking of existing alphabetical sort ("magic behavior"), we could offer a check box at "Sort subgroups") and store it as property of the group. (Source: JabRef#10066 (comment))