1) Ok Michael, I know the trick, but I prefer to have that option. For example if I have a LOT of polygon to copy, I prefer to click that option, instead of delete those after.
2) As I already mention before I don't know about it, so you are fine.
3) I don't really understand the real problem with stretch in moi. I know that in some case, I make same boolean operation , and after that I cannot edit the result in moi. I know that could be difficult to handle, but I don't understand it...
4) For sure that helps a lot in my case. Thanks. I try it tomorrow but I'm sure that is what I need.
I want to say that I know that this personalization are probably not useful for a lot of people, but I really like the way that moi can be modified. So thanks Michael and thanks to all the other that are tried to help me in personalizing this WONDERFUL SOFTWARE.

Luca