I previously removed the sorting logic from SortFilter thinking it was
unnecessary if we construct the model with a sorted list. However, this
only worked when no pattern was set, and the items are misordered as
soon as a pattern is input.
This patch reintroduces alpha-sorting, which can be disabled by passing
sort=False to the ListCategory constructor. The session completion test
had to be tweaked as it simulated the incorrect assumption that the
session list is not alpha-ordered; sessions come out of the
session-manager pre-sorted so we may as well use alpha-sorting in the
session completion model.
Resolves#3156.
47447c047a