when i am trying to navigate through my infopath form with TAB key it is struc at dropdown field(two), some other dropdown fields are working fine. i replaced them with new dropdown field but no luck.
Is this a browser form or filler form? Have you checked the Tab Index property of your dropdown control?
i did, that set to dafault i.e. 0. its not a browser form, it's in infopath 2007.