Objects keep duplicating

[Anonymous]

I am designing an apartment block for my course and when ever I try to copy my floor layout (second floor) to another floor (third floor) objects keep duplicating (walls, tables, shower), it doesn't happen to everything. I am using 'Edit - Move - Edit Elements by Stories. I have also tried use 'copy' then going to another floor plan and 'pasting' there but it still duplicates.

[Podolsky]

You also can check - are your library parts (furniture) shown only on home storey. Because it's possible to set them to be shown one storey above too or on all storeys. That also might give an impression of duplicated elements.