set_store doesn't trigger createMemo unless I set the store to undefined first.

        set_for_board(_: NewOrInProgressPuzzleForBoard, ls_key?: LSKey) {
            console.log('set_for_board', _, board_state.raw_for_board)
            batch(() => {
                set_board_state('ls_key', ls_key)
                set_board_state('raw_for_board', undefined)
                set_board_state('raw_for_board', _)
            })
        },

   const for_board = createMemo(() => {
        let f = board_state.raw_for_board

        console.log('tracking memo', f)
        if (f === undefined) {
            return undefined
        }
        return PuzzleForBoardWrap(f)
    })

    const [board_state, set_board_state] = createStore<InternalBoardState>({
        ls_key: undefined,
        raw_for_board: undefined,
        loading: false
    })