Redwood UI Default Subinventory and Locator if an Item Is Only Assigned to a Single Location

In the release notes, it states

Now, the application will default the subinventory for a transaction if the item is associated to only one subinventory within the organization without any defined item transaction defaults.

but then states

This behavior is currently only applicable to existing transactions that already use item transaction defaults.

The notes also is mentioning 'the mobile'.

When I am in the Configure Subinventories page, and I click on Create by item, add my item inforamation, the Create button is grayed out.

Not sure what I am missing. It states you dont have to assign ITDs but hen it says this is only applicable to existing transactions that use ITD. Do you still set up ITDs or not?