Hi Michael,
for first thing I want give thanks to you for the last Beta.
I send you a file and an image that show a surface that I have realized with the system of scaling rail, but the result is bad and unexpected. Is this a bug or other problems?

I want ask you, if in a next future is possible to insert a command that we can use to extend the surface, because actually, if I don't wrong, the extension is used only to extend the curve and not the surface. About this command I need some information. should explain to me why if I lengthen through the tool you extend a curve which has produced a surface for instance extruded direction a other existing limit superfice the produced surface does not keep himself up to date
following curve lenghtening have tried to activate History but has not worked, Why?
Besides, about the History, can you teach me the best use of this command with the situation more complex, because now I am able to use the history with the easy situation as copy or mirror etc.....
Of course..........if you could, since I have some problem with the English language.
Could you help me understand the history command explanation well with help of some image?

Thanks for everything, also of the big patience which you show answering us