Help with Curtains. (Calling All Builders, even users of CC)

If you have issues with curtains snapping to the windows when you don't want to, there's a trick to avoid it.
Temporarily move the window to a completely different place. Then place the curtains. Move the window back to its original place.

Also, seeing as windows and curtains are both non-functional objects, it's relatively safe to use the move objects cheat.
Just make sure to turn it back off before placing any functional objects.