Hate to add to this but I'm having the same problem...no problem so far with other items in the library...the knowledge base instructions don't seems to work in this instance...when I select a rug and move the cursor to the plan nothing happens...when I click over the room area it just overlays the room with the gray box...using Architectural 2017....tried Kenneth's suggestion but I just see the library window...no dialogue box....
Any help would be appreciated....
Jim