BUG: setAlphaField: fix incompatibilities with BCs (#1962)
Co-authored-by: Johan Roenby johan.roenby@gmail.com
Co-authored-by: Henning Scheufler Henning.Scheufler@dlr.de
Co-authored-by: Johan Roenby johan.roenby@gmail.com
Co-authored-by: Henning Scheufler Henning.Scheufler@dlr.de