Another proper course question
We were racing the other night and encountered a situation that caused some confusion for us.
Another boat gained an overlap to windward while we were both on a close-hauled course. They were able to point higher than we were and were asking us to head up but we were unable to go any higher. The question is do we (the windward boat that has been overalapped) have to keep clear? Or can we continue to sail our proper course which will force them down off of theirs or force them to duck behind us?
Rule 17 talks about the boat gaining the overlap not sailing above their proper course but I am not sure what rights the boat that has been overlapped has?