Railing wall removes floor of adjacent room

[C4Adrafting]

I'm sorry I can't post the plan...still too big after compressing.

In the image I've shown a wall between a Loft space that should be open to the Great Room below. When the wall is selected as an invisible or solid wall everything is fine, but when I switch the wall type to Railing, is acts as if the wall definition is removed and the two spaces become a single room. It was working perfectly yesterday, but I broke it today. Any ideas what I'm missing?

Thanks,

[MoeGia]

It should work.  My guess is the railing wall is not connecting with your dormer wall properly.  Try a short perpendicular invisible wall where the two wall types meet.  That should give you your room definition.