Categories - Structural Columns

Today I came across a problem with an elevation view. A colleague of mine had an in-place family representative of a series of existing walls. (Not how I would recommend normally doing it, but beside the point). They then created a joinery family (aka casework) and placed it within the perimeter of those existing walls. So far so good. An elevation was created to look at the front of the joinery but instead of seeing joinery, we only saw walls.  

(Note: I created a very simple example recreating the problem)

The elevation shown in front of the joinery, surrounded by an in-place family of walls.

The resulting elevation above. No joinery can be seen here.

So I started my usual process of elimination, starting with checking where the elevation line was, view extents, visibility graphics, filters, etc etc. 

I finally noticed when selecting the in-place family (representative of the existing walls), the category assigned wasn't in-fact 'Walls'. It was 'Structural Columns'. Ah huh! So we updated the category to walls and there appeared our joinery in the view! 

The view with the in-place family category set to 'Walls'.

Just another thing to add to our list of things to check when troubleshooting. Worth noting this difference in behaviour between the categories too.