Drasil: In-text citation References are included in traceability matrix

[bmaclach]

If a source is cited in-text (for example in an assumption, or in the Notes field of a definition or model) then the traceability matrix will include a row for that source, however the row label is blank, like below:

I think that sources should not appear in the matrix, but even if I'm wrong about that there's still the bug where the row label is blank.

Note: Sources appearing in the "Source" field of a TM, GD, DD, or IM do not trigger this bug.

[Mornix]

I think I may know what the issue is. I should be able to tackle it in conjunction with #1164.