As a daydreamer myself who has tried to channel that tendency in a productive fashion...
Have you tried to get her to write? Great poetry and fiction (ala Agatha Christie!) can come out of people with glazed-over eyes.
Even if her compositions are created on a voice recorder or some other oral method--in case handwriting slows her down too much--it might be a way to get her out of dream mode in her day-to-day life.
I don't know if it would work, but it might help.
FWIW (not much), she doesn't sound ADHD to me. Just not interested in what's going on in school when she can turn to her rich imagination instead. But I'm about as far from an expert on the subject as you can get!
