Objects going through other objects

[Lateralus]

I am completely new to scripting and all, but playing with this level editor has sparked some interest in it. I'm getting used to the program fairly quickly but I am having one problem. Sometimes objects are noclipping through other items, for example a note placed on a table has parts of the table showing through the note. And a dynamic painting placed over a secret wall will have areas of the wall showing through. Any help is appreciated, and thanks FG for an amazing game!

One more thing, what walls should I be using when I place stairs? Tilting default walls do not match up with the normally placed walls.