I just saved a slab as a ‘stair tread component’ and can see the 3D preview with no problems.
As I amend the script the preview changes.
There was no 2D preview as it didn’t generate a 2D script.
Do you have the correct subtype (“tread component”) selected?
Versions 6.5 to 22
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision M6800 - i7 4700MQ @ 2.40GHz, 16GB RAM, AMD FirePro M6100 (2GB), Windows 7 64bit