Add hints to sort rule selection when empty #5967
Description
Description
If no sort rules have been added, the lists (in the book sort view, and in settings) will only show a -- None -- option. It would help to have a hint here, when empty, about how to create a sort rule.
Maybe we could just have a link to create, regardless of whether empty or not, although we'd need to also think about an alternative for if the user does not have settings-manage permissions.
Related to support request 190.