The thing is I did that.. I ran around my entire house doing that and it placed nothing, the walls are 2 blocks thick and i placed walls in the middle of those (in case it was counting the outer walls as the room) and still nothingDid you make sure the furniture (bookcase, bed, dresser) has walls behind? Just in case, if you carry a stack of walls with smart cursor toggled the cursor will tell you wherever you are missing walls.
Don't ask why it is called Happy Little Accidents.. Upon spawn, just go right, there will be big NPC house, and it's on the right of that.Well, in that case as stated before, could you upload your world file? It should be located within your documents folder in the subfolders My Games/Terraria/Worlds/YourWorldName.wld
Just make sure not to move/delete the file or your world will POOF.
2) I'm not sure but if you actualize blocks within the house you may have to put background walls underneath as well.