It does currently work in the stable build. It just doesn't have a ghost image of where you're putting it, nor is it represented by a model in game. You can attach it anywhere on your base, swap to pipes and they automatically connect to it.
Never mind, found the solution. Apparently the multipurpose rooms weren't counting as being fully built, it would let me inside them and build on top of them as well as place ladders etc. But it would still let me deconstruct them with everything in…
As far as I can tell it only happens when exiting the game; in hardcore mode anyway. It looks like the OP is playing in survival mode as his save button isn't greyed out. So I'd imagine he'll be able to save it any time he wants.
So with this new update I noticed that there's a save button, which I love the idea of rather than having to quit to desktop whenever you want to save.
Although my save button is greyed out permanently. I assume that's because I play on hardco…
So with this new update I noticed that there's a save button, which I love the idea of rather than having to quit to desktop whenever you want to save.