Sorts are biased by previous sort columns.
Since both do not have a Series, the sort order (of blank Series) will tend to from what was before that.
There is a tweak that might also come into play after certain actions that cause resorts
[CODE][/ID: maximum_resort_levels
Set the maximum number of sort 'levels' that calibre will use to resort the
library after certain operations such as searches or device insertion. Each
sort level adds a performance penalty. If the database is large (thousands of
books) the penalty might be noticeable. If you are not concerned about multi-
level sorts, and if you are seeing a slowdown, reduce the value of this tweak.CODE]
|