[md][cc] Dirichlet-Dirichlet coupling does not work with setCouplingDirichlet
For a Dirichlet-Dirichlet coupling, the boundary volVars of the own domain receive Dirichlet values from the other domain thus need to be deflected properly.
This only works if
setDirichlet() is used in the poblem, not if
setCouplingDirichlet() (which would be more intuitive).
The elemVolVars consider the boundary types'
hasOnlyDirichlet which does not take
couplingDirichlet into account.
One possible solution would be to also consider
What do you think?