One more btx issue.

The output from the following

    \startbuffer[TestBib]
    @FILM{Film1,
       producer     = {Lasta, A.},
       director     = {Lastb, B.},
       title        = {Title1},
       year         = {2017},
       publisher    = {Publisher},
       address      = {Address},
    }
    @FILM{Film2,
       producer     = {Lasta, A.},
       director     = {Lastc, C.},
       title        = {Title2},
       year         = {2017},
       publisher    = {Publisher},
       address      = {Address},
    }
    \stopbuffer
      \loadbtxdefinitionfile[apa]
      \usebtxdefinitions    [apa]
      \usebtxdataset        [TestBib.buffer]
      \definebtxrendering   [Pubs][apa]
    \enabletrackers[publications.authorhash]
    \starttext
    \placelistofpublications[Pubs][method=dataset]
    \stoptext

is incorrect. The director of the second film is lost, and the use of a 
bib dash makes it look like Film1 director is associated with Film2. 
There should be two separate entries:

    Lasta, A. (Producer), & Lastb, B. (Director) (2017). /Title1./
    [Motion picture]. Address: Publisher.
    Lasta, A. (Producer), & Lastc, C. (Director) (2017). /Title2./
    [Motion picture]. Address: Publisher.


-- 
Rik