Design Explorer is a really good new feature in JMP 17 for comparing multiple candidate designs in Custom Design. However, you can't utilize it if there are Fixed Blocks, Random Blocks, or Hard-to-Change factors in the experiment. So this is a bit limiting.
I'd like to see new versions let you utilize Design Explorer for these scenarios.
In the current version, it is slightly misleading because you can check the box for Random Blocks initially, but the Design Explorer menu will then drop it in subsequent evaluations. I did not notice this until after a run sheet was generated. The initial setup screenshot is shown below.