How are views to be formulated for nested class instances?

I'm trying to create a user interface for a class that contains instances of other classes. Here is an illustrative example:

from traits.etsconfig.api import ETSConfig
ETSConfig.toolkit = 'qt4'
from   traits.api   import HasTraits, Instance, String
from   traitsui.api import Action, Controller, Item, View

import sys, traits, traitsui
print ('python version   :',sys.version)          # 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 08:06:12) [MSC v.1900 64 bit (AMD64)]
print ('traits version   :',traits.__version__)   # 4.6.0
print ('traitsui version :',traitsui.__version__) # 5.1.0

class Name (HasTraits):
    first = String
    last  = String
    view  = View (Item('first'), Item('last'), title='Person Name', buttons=['OK','Cancel'])
    def __str__ (self):
        return '{} {}'.format(self.first,self.last)

class Person (HasTraits):
    name = Instance(Name)
    view = View (Item('name'), title='Person Info', buttons=['OK','Cancel'])
    def __str__ (self):
        return str(self.name)

class Datastore (HasTraits):
    def add (self, person:Person):
        print ('added', person)

class Contacts (Controller):
    add  = Action (name='Add', action='_add')
    view = View (title='Datastore', buttons=[add])

    def _add (self, info):
        person = Person (name=Name())
        save   = person.configure_traits (kind='modal')
        if save:
            self.model.add (person)
        else:
            print ('user canceled ADD action')

datastore  = Datastore()
controller = Contacts (model=datastore)
controller.configure_traits()

It seems I have to use kind=modal to pause execution in the Contacts._add method while the user enters information.

A typical user interaction is:

1. Click the [Add] button in the Datastore dialog. The Person Info dialog appears.
2. Click the [Name] button in the Person Info dialog. The Person Name dialog appears.

Problem is: the Person Name dialog can not be made active because Person Info has focus.

How can the desired behavior (giving Person Name focus) be achieved?

Thanks.

If you wish to have different windows for the different views (rather than one window with nested views), you could also make the call to person.configure_traits into a call to person.edit_traits and pass in a Handler that adds the Person instance to the data store when the window is closed.

More specifically, I changed your controller to

class Contacts (Controller):
    add  = Action (name='Add', action='_add')
    view = View (title='Datastore', buttons=[add])

    def _add (self, info):
        person = Person (name=Name())
        person.edit_traits(
            handler=PersonHandler(datastore=self.model)
        )

The handler is passed a reference to the data store, and adds the person to it when the user clicks "OK":

class PersonHandler(Handler):
    """ Handler class to add a person to a datastore.
    """
    datastore = Instance(Datastore)

    def close(self, info, is_ok):
        if is_ok:
            print('adding to datastore')
            self.datastore.add(info.object)
        else:
            print('not added')
        return super(PersonHandler, self).close(info, is_ok)

Full code sample: https://gist.github.com/jvkersch/e72f2fb4ed72b2e9ba8269c6a6a2957a