1) Sort the Library by a column that displays line by line, e g Last Updated.
2) Secondary sort by a column that displays with collapse/expand groups, e g Series.
>> The Library displays as if you had sorted 2) before 1).
(My Last Updated column was 'cluttered' with so many Texts and Studies: Contributions to Biblical and Patristic Literature volumes that it was hard to see what else was there. I was hoping that a secondary sort by series would keep the date order intact and only sort the series within the dates, thereby conveniently collapsing Texts and Studies into one line.)
I realize this is a bit of a challenge to design and code, but whatever you do with it, it shouldn't behave like this. If you won't make it work, it would be better to refuse the secondary sort and instead display a popup telling us why it can't be done.