Frederick, you were on the right track, but rvietor was unaware that DT does support what you want … it’s just not well-documented! See my proposed additions to the DT user manual at:
I’m cleaning up the text and will submit a pull request for this update soon, but I have not yet found any error or substantial omission in what I’ve written to date.
@BillC : It may be just a matter of how I read the original request. For me “sorting by” means sort using the values of a variable (e.g. filename, date, iso). Tags don’t have values (*), so you cannot “sort by” a tag. Of course, a custom sort (or any of the defined sort orders) on images selected by a tag should work.
(*: unless you consider them booleans, then they can have two values)