3-D Workspace: What does "unlayed out view" mean

The 3-D Workspace of the stuart platfrom example

https://de.maplesoft.com/products/maplesim/modelgallery/detail.aspx?id=34

displays as follows. Clicking on the central object I get

Q1: What does "Unlayed out view mean"?

Q2: What is actually displayed in the center?

Q3: Why is only one leg shown in instead of 6?

I would really appreciate more insight into the 3-D Workspace. I use it to inspect structural integrity of models and assembly errors, but I am often lost by its behavior.

Thank you!

(I have tried to work it out myself with online resources, Maples help system and MapleSim user guide.)