Session save for WM4

The latest build of WM for me doesn’t prompt for a session save, and I can’t manually save either. It has saved a session by itself on a bug once, but that never happened again.
Are session saves not implemented yet or is it something wrong with my WM?

You have to go to “file>advanced>start session” in order to save session files. They work differently now though, build results aren’t saved (or at least that’s my experience. Not sure if this is intended behavior now, could be since interactive preview is now a thing).