Time stepper info absent in archived ChSystem

[Haifei Chen]

Hello,

I'm archiving ChSystem object to compare the output files by running Chrono directly and by running through an interface coupled with a third-party code. It seems the time stepper info is missing in these files (see attached). I could reload the archive and time step the simulation if the default solver/integrator is used before archiving ChSystem. But there is 'segmentation fault' if other solver/time stepper (eg. MINRES/HHT) is specified. 

Also, why 'First(sys)', instead of 'sys', is in the JSON file archived by my coupling interface?

Thanks for your help!

Haifei