major
nice-to-have
defect
major
enhancement
You can create new types within the app, but there is no general way to create new instances of those types.
Improvement
Even without a specialized GUI, it should be possible to create and edit new instances of any type in the system (as an administrative feature).
Test
In the Administration:Basic Administration view, select the " Flat A " type, then create a new row in Administration:Basic Administration:Attributes:Instances, enter values, and save.
An automated test is not currently feasible because, due to duplicate type names (one for the abstract supertype and one for the concrete subtype), the type tree cannot be scripted to the extent that a specific subtype could be uniquely selected.