View a simple, structured or compound data type

We're trying to solve two big issues with this dialog:
I) the definition of a simple (basic) data type; and
II) the definition of a structured data type.

• The first one is kind of easy, we just need to provide to the user an input and a select, in order to capture the name and the type of a simple data type.
• The second problem is a little bit more difficult. Because the user needs to be able to define complex data types, with nested structures. For example, the user can create a data type called Person with 3 nested fields (they are simple data types) Additionally, a structured data type can have other complex nested data types.
• Requirement to address situations where we're going to have many levels of nesting and many fields. The user should be able to: a) navigate between levels; b) expand/collapse nested types; c) create complex data structures easily.