You can't place door on other floors as of now. It has a lot to do with the way doors are implemented at the moment. I might have a fix for that but don't get your hopes up.
The engine historically only had other floors for decoration.
I was very surprised you can jump on different floors anyway :D
P.s.: I'm very thankful for your work! It's a great editor.
Thanks )
I'll try to make it even better in future!
