There's no reason an online hosted Web IDE can't work perfectly well in an offline mode too. Offline-capable Web apps are essentially a solved problem.
> Offline-capable Web apps are essentially a solved problem.
That may be true in theory. In practice "essentially" is an awfully long way from "absolutely", with offline support in many apps being either choppy or non-existent. Even the venerable Google Docs is something of a ####show when used offline, to the point where I gave up and went back to Office 365.
