Meta -> Source property not saved

[uwestoehr]

Word size of FreeCAD: 64-bit, Version: 0.18.15780 (Git)
Build type: Release
Branch: master
Hash: f94e76c1116ec3b818961ff65131b3d86fa5b95e
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0

The material property Meta -> Source is not saved:

- add a material, then "use FreeCAD material editor"
- load a FCMat file, e.g. the attached
- change or add something in the property Meta -> Source
- Save it under a new FCMat file name
- press OK and again click on "use FreeCAD material editor"
- load the just saved FCMat file

result: the value for Meta -> Source is lost, the field is empty

[uwestoehr]

result: the value for Meta -> Source is lost, the field is empty

This problem persists also with the recent fixes to the material editor (FC 0.18.15805).
Therefore I created issue #3824 for this data loss bug.

[bernd]

https://github.com/FreeCAD/FreeCAD/pull/1966