Hi Mike,

> Just for development notation: I intuitively tried to hit the delete key
> and the "X" to make a knot disappear. (wishful thinking) ;-)

Which knot would disappear though? Since there isn't currently any way to select a surface knot line there isn't a good way for me to know which particular knot line to remove when you push delete, that's the problem...

It probably needs a special command for it that shows you the different knot lines on the surface (which are certain surface isoparm lines, in between surface spans) and let you pick those.

- Michael