Subject: Subgroups for Environmental Parameters not implemented

After adding a subgroup to environmental parameters
I get:

da_get_para_tree ('ENV', '%', '%')
An unhandled exception occurred:
Traceback (most recent call last):
  File "/powerhome/frank/projects/greater2/thuban/Thuban/UI/mainwindow.py",
line 206, in invoke_command
    command.Execute(self.Context())
  File "/powerhome/frank/projects/greater2/thuban/Thuban/UI/command.py", line
121, in Execute
    apply(self.function, (context,) + self.args + args, kw)
  File "./Greater/Modules/session.py", line 810, in open_session
    context.session.SetSimulationSession(SimulationSession(sess_record))
  File "./Greater/Modules/session.py", line 148, in __init__
    self._get_environment()
  File "./Greater/Modules/session.py", line 439, in _get_environment
    self.SetEnvironment(Environment(records[0]), delete_res = 0)
  File "./Greater/Modules/session.py", line 463, in SetEnvironment
    environment.SciParams() # dummy call to ensure the
  File "./Greater/Modules/parameterblock.py", line 65, in SciParams
    self._full_initialization()
  File "./Greater/Modules/parameterblock.py", line 126, in _full_initialization
self._create_parameters()
  File "./Greater/Modules/parameterblock.py", line 151, in _create_parameters
d = self.new_det(r.field_id, r.block_id)
  File "./Greater/Modules/parameterblock.py", line 99, in new_det
    raise NotImplementedError
NotImplementedError