All the other settings on the "Symbolic Representation Settings" tab of the "Structural Settings" dialog are accessible, but the "Plan representation" pulldown (values can be "Line with Angle" or "Parallel Line") is not - see the green in the attached image. It's silly to have all the others available, but not this one.
My original forum post: Re: How to access 'Plan representation' setting in Structural Settings? - Autodesk Community
