There might be a reason they chose to make it disabled if you didn't do that.

@KevinJ of Kansas just wanting to understand. why is it a bad habit to hide or disable a field on a form? do you mean if there is a workflow using the form then the change to the form should occur at the workflow level?

It can make troubleshooting more difficult if you bury the custom form selecting field. Hiding other fields is fine on the form