DWSim's main advantage is its thermodynamics and properties functinality. If you do not need them, you may be better of trying general purpose environments: https://www.scilab.org/software/xcos https://www.openmodelica.org/?id=78:omconnectioneditoromedit&catid=10:main-category I am not sure, but SciLab/Xcos might even use soem simple m-sripts...
I am afraid there is some problem with mono, not with DWSIM, as I checked also older...
Adding components in mono edition