Ok, I have been trying to replicate this and at this point, I am thoroughly confused by your post and what exactly the problem is.
I built a single floor building on a foundation and put a basement under it and raised the foundation. Then I put a pool on the first floor in the middle leaving space all the way around. For the floor I used the Crystal Clear object that came with IL to floor over the bottom of the pool (had to use MOO) and then used the 2 tile double pane windows around the sides of the pool.
Is this what you did?
In the 1st picture, it looks like you are trying to place the chessboard and chairs in the pool or intersecting the pool wall. Which the game doesn't allow unless you use MOO.
In the 2nd picture, it looks like the object dropped to the basement while you are on the 1st floor but I can't replicate that. My objects stay on the 1st floor. I have to drop to the basement to place objects on that level and had no problem doing so. Everything seems to work fine for me.
So are you saying that objects placed in the area outside the pool on the 1st floor are not placing and dropping through the floor even though you can see the floor? So the game is acting like there is no floor at all?
If that is the case, you might want to try this. Click on one of the rooms around the pool. Then click the floor and see what it says. If it gives you the option to remove floor, click the X and remove the floor. Then redraw the walls around the room. That should replace the floor and the ceiling below. You'll probably have to redo the wall paint and floor tile but it might fix the issue.
If you don't get the remove floor option, then drop down and select the basement. Go back up and you should see a yellow outline. Click on that and you should see remove ceiling. Click the X and then redraw the wall around the room on the 1st floor. That should give you the 1st floor floor and the basement ceiling back.
Hope this helps.
