I love the virtual whitespace most of the time but is it possible with the API, to prevent it from affecting only the contents of block comments? It tends to clobber the leading space.

No there is no such option yet, but I agree there should be some work on how the block comments are handled. It is not a top priority right now, because I want to get unicode support first, but once I am done with that I will return to virtual whitespace to make it better and hopefully make it customizable.