What are you building on top of VNC, and where does the protocol get in your way?

This group is for people embedding, automating or extending rather than just connecting.

What are you building, and what did you have to work around? Encoding negotiation, clipboard
behaviour, authentication, session lifecycle: the awkward parts are the ones worth writing down,
because they are the ones missing from the documentation.

If you have written a client or a wrapper, we would like to hear what surprised you.