So continue using DVDDecrypter, that's what I do. [shrugs]. I ran into that problem myself with an earlier version of DVDFabDecrypter. Hmm, IIRC I was testing it with "House of Flying Daggers". The DVDRB trick didn't work in that instance, although, as you've noted, the DVDDecrypter/DVDShrink combination works fine.
In case anyone's interested, earlier versions of DVDShrink will work with DVDFabDecrypter output. Out of curiosity, I tried DVDShrink 2.3 and 3.0beta5. As expected, Shrink would not open the VIDEO_TS.IFO and threw an error message. Those versions, however, let you choose the VTS_01.0.IFO (usually the main movie, the numbers may vary). Shrink will complain about that also, but close the error message and it will nevertheless open it. From there you have a choice, backup or reauthor. In the former case, you can retain the menu, but it will not autoplay unless you correct it in IFOEdit. (The menu will be accessible via your remote). The latter case is main movie only.
In either case, you must recreate the VIDEO_TS.IFO or video manager. When done with DVDShrink, open the files with DVDFab 0.17 freeware (NOT DVDFabDecrypter). Click "create video manager". Done. Or do it in IFOEdit.
At the risk of being repetitious, there is NO goddam reason to abandon DVDDecrypter. Hear that, everybody? It's still better than anything else out there, and if (when?) you run into a movie it can't handle, just create a protected sectors list. It ain't hard: