After checking this I have little update of the situation. So when you are creating new process you will currently don’t see options for VB or C# process type:
So C# support was under experimental features. Right now we are focused on having your feedback about exact features of current preview version of Studio 2019.10. Those features will be delivered to our LTS release and this is why we have removed from current preview version all experimental features.
Sorry for inconvenience, this should be back ASAP
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