Hello, I am the Dark developer.
For the uninitiated, dark is the decompiler of the Windows Installer XML toolset. When initially conceived, dark was a combination of programming project in C# and a way of getting WiX users off the schnide. Unexpectedly dark was used by more folks than I imagined to make up for the gaps in WiX documentation via decompiling their existing MSI. Now that WiX has been in the open for a year, the documentation is much improved (there's even a tutorial), the community has another source for "start here" the users expectations for dark have shifted.
"Roundtripping" is emerging as the new default expectation from Dark. What is roundtripping? In the WiX semantic, it's running a MSI through dark, then candle, then light and expecting the same product as the original MSI. I sometimes call this "dawn" or the "dawn cycle" but the name isn't as satisfying as I'd like. Roundtripping turns out to be harder than one might expect as there are a lot of variability to the way folks have built their MSIs. Given I'm just a volunteer (along with the rest of the WiX crew), the needed research to get every last detail correct is time constrained.
Still, if you find a round tripping bug, please post a bug and I'll get to them as time allows. I'll get to them faster if you've mastered the technology you're converting from and can give me guidance on what I've missed. Fair warning: VSI (Visual Studio Deployment Projects) are the most requested and the least known on my part.
Thanks for your patience. Hope this helps...