Basically every release we look at if it's possible to get us to tabs in that release window. If it's not, then usually we'll do some architectural work to get us closer to that goal. Part of the problem is that most of the codebase is from 1993, so there's a LOT of architectural work between where we were when Windows 10 first launched, and proper tab support.

We're working hard on that architecture stuff now, because we want tabs just as bad as the community.