In Work mode, on my board, my subtasks are hidden.
My filter looks like this: Component = Foo.
The subtasks don't have the Foo component
So what do I do....adjust the filter to query on parent values (doesn't seem possible)...add Foo to subtask and keep its value always in sync (doesn't seem possible)...add a custom field (doesn't seem to help) something else?
Having boards as filters is a nice idea, but it doesn't really work for even really simple stuff, like A= B.