In the Family Element Visibility Settings dialog, you can specify if elements are display in plan or elevation Views.
We need to separately specify Plan and/or RCP.
There are often elements that are displayed in Plan but not RCP or vice/versa.
And if you're going to go in there, give me a check box for 3D as well.
I often want elements (not Linework) that are NEVER displayed in 3D, but are displayed in "2D" Views.