Welcome to the Discourse!
This isn’t actually a bug, We’ve never been able to place doors and windows using the slab tool, There is a awesome tutorial on how to add doors and windows to slab structures, Which can be found here:
http://discourse.stonehearth.net/t/placing-doors-and-windows/13661
I think its a planned feature, (Don’t hold me to that 
) But as far as I’m aware its never been possible, You’ve always got the grow wall tool though when making normal buildings. As for roofs, at this point you’d also need to draw them up yourself on slab structures.
Hope that helped 