Can no longer select 3D symbol

[Evolution]

I used Hover to import the symbol of the existing home into my plan. Now that I am working on the new addition, the 3D symbol was getting in the way, so I assigned it to a "terrain feature" layer to be able to turn it on and off as I worked.  Building department said I had add a means to connect the addition to the main house, so the home owner would not be limited to the max sq ft available, so I added that to the floor plan.

 

I now am attempting to turn the terrain features layer back on so I can see how the new connector will work, but even though the layer shows that it is turned on, it doesn't display in my floor plan. I am no longer able to select and open it either. It is obviously showing on the plot plan, but not the floor plan.  In each case the Terrain Features layer is on. 

Would you mind taking a look and see if you can figure out what I did / didn't do correctly? I did an all on layer etc., and still cannot select the 3D model.

I'm really sorry to keep bothering you folks with such trivial stuff

YARBRO_RESIDENCE_ADDITION.plan

 

[Evolution]

12 minutes ago, solver said:

All Layers On layer set, select all, unlock.

Eric, I know you won't believe I did the All layers on, and I must be going blind, I didn't see that I'll try harder next time, or just quit posting my questions