Subtasks put task in Todo for Kanban

[arnt witteveen]

In the board for a Kanban project, a story is stuck in the TODO part of the board, even though it shouldn't be there according to the filter.

The reason seems to be that a subtask should be there according to the filter.

How can I set things up so that when I drag a story into the TODO part of the board, I see it's subtasks (without manually having to edit the state on each one), but when I drag the story out of the TODO part back to the backlog, it is gone from the TODO part (and not stuck in there in grey due to the state of the subtask?

I guess I could move the subtask to the state that goes into the backlog, but then if I add the story to the TODO column, the subtask will remain hidden I think, which is of course also not what I want.