Hi there,
If the DVD is a dual layer one (DVD-9), there is a layer break, and whenever there is a layer break, the subtitle's Vob ID is changed from 1 to 2 (be sure not to mix up with Vob Cell). When I authored my final output, IFO Edit did not recognize when it reached the subtitle's layer break (i.e. where subtitle's Vob ID changing from 1 to 2), therefore, the 2nd half of the movie had NO subtitle at all. How can I change the subtitle's Vob ID (use "1" for the whole set of subtitle) so that IFO Edit will recognize it? By the way, I used VOB Edit to rip my subtitle stream. Thanks in advance!

I used subresync.exe (a file inside VobSub.zip) to check, it showed subtitle's Vob ID.