It's what currently is being used by the Sigil process.
If you work on something, why would you "quit" it before it's finished? In a world of bugs and memory leaks, I get that there may be reasons for restarting programs, but that's a work-around, not a good workflow.
If it makes it too hard to find any bugs, ok, you guys are doing a fantastic job and you choose what you work on. Nemas problemas
I took the chance that it may give you any clues.