Not clear to me how the "Play with Play Doctor" integration works (I'm not subscribed to Cloud Play). It always seems to yield "no search results". Add a Help page to the wiki
My experience re how it works today:
Any selection rules which are set under
Play Doctor > Options > Set Rules... act as a prefilter for Search DJ's "Play with Play Doctor". In this case only those items which get through the prefilter become candidates for the list displayed by Search DJ. When Search DJ succeeds in listing something requested, then filtered items which are not explicitly requested by Search DJ may also be displayed ("related items").
Search DJ's "Play" button ignores
Play Doctor > Options > Set Rules..., i.e. no prefiltering.
Example: Set
Play Doctor > Options > Set Rules... to "genre contains Jazz". Then ask Search DJ to list artist Lana Del Rey, whose music I have
not tagged for genre Jazz. No items are found for "Play with Play Doctor", however "Play" lists her material from my collection. Then ask Search DJ to list artist Miles Davis. "Play with Play Doctor" lists much of my Miles Davis material, as well as some of my other Jazz tracks. "Play" lists only Miles Davis.