FBbt save to OBO from Protege fails

[dosumis]

The only way to edit in Protege right now is to save as OWL and then convert back with some other tool (roundtrip via ROBOT works).

I suspect this explains the problem: protegeproject/protege#501

This means we can fix by tweaking the OBO file.

Possible clues from log:

This looks suspicious:

2018-04-20 18:22:07.753 [pool-3-thread-1] WARN OWLAPIOwl2Obo MASKING ERROR «Conflicting id definitions: 1) composed_primarily_of 2)RO:0002473»

(There are also lots of these:
2018-04-20 18:22:07.730 [pool-3-thread-1] ERROR OWLAPIOwl2Obo Duplicate clause 'alt_id( FBbt:00002794)' generated in frame: FBbt:00002786

but I think probably a harmless artefact of move to generating stanzas from alt_ids.)

[dosumis]

Fixed. Duplicate stanza for RO:0002473 - one direct, one via xref used for conversion.