> Therefore, I would like to change
>
>   (put-text-property ell-beg (point) 'invisible 'dired-filename-hide)
>
> to
>
>   (let ((ov (make-overlay ell-beg (point))))
>     (overlay-put ov 'invisible 'dired-filename-hide)
>     (overlay-put ov 'isearch-open-invisible t)
>     (overlay-put ov 'evaporate t))
>
> in the attached patch, then text in hidden part can be matched
> regardless of search-invisible being open or t. It also has a bonus
> that hidden text can be revealed during isearch.

Since there is no objection to using overlay, I have updated the patch
accordingly with additional explanation. Thanks.