This is what is happening to me: I've installed Archistair 1.09 in my computer, and when I begin the creation of new stair everything goes normally through the creation dialog box. When you finish to introduce the parameters of the current stair and hit create.... voilá. Nothing happens. I've installed it on another computer and it works fine.
Stair layer active and visible. That's not the problem. Please follow the link to the discussion I've had with Fabrizio Diodati about it. And if you find an answer I'll be grateful.
