[Paraview] GetSources() fails with Custom Filters

[m.c.wilkins at massey.ac.nz]

Hi,

Under 3.6.2 on linux in the python shell GetSources() fails if there are
sources in the pipeline browser that appeared from Custom Filters.  The error
is:

>>> GetSources()
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/home/kitware/ParaView3/Utilities/BuildScripts/ParaView-3.6/ParaView3Bin/Utilities/VTKPythonWrapping/paraview/simple.py", line 195, in GetSources
  File "/home/kitware/ParaView3/Utilities/BuildScripts/ParaView-3.6/ParaView3Bin/Utilities/VTKPythonWrapping/paraview/servermanager.py", line 1493, in GetProxiesInGroup
  File "/home/kitware/ParaView3/Utilities/BuildScripts/ParaView-3.6/ParaView3Bin/Utilities/VTKPythonWrapping/paraview/servermanager.py", line 1704, in next
  File "/home/kitware/ParaView3/Utilities/BuildScripts/ParaView-3.6/ParaView3Bin/Utilities/VTKPythonWrapping/paraview/servermanager.py", line 2280, in _getPyProxy
  File "/home/kitware/ParaView3/Utilities/BuildScripts/ParaView-3.6/ParaView3Bin/Utilities/VTKPythonWrapping/paraview/servermanager.py", line 2339, in _findClassForProxy
KeyError: 'Foo'
>>> 

What I am doing is creating a Custom Filter (Foo) by: selecting two filters I
have applied, clicking on Create Custom Filter, then taking all the defaults
(clicking through Next Next Next, then Finished).  Then I apply that custom
filter, then run a GetSources() in the python shell and the above error
appears.

I friend tried the above with 3.8.0 on Windows with similar results.
I don't completely trust he did it right, but he probably did, so the
problem is probably not limited to 3.6.2 on linux.

Have I done something wrong with my Custom Filter?

Thank you very much for any help you can offer.

Matt Wilkins