Comments by Sherdz (Top 3 by date)

Thanks Prasad, I looked up everything I could find about Zedgraph before I posted.
The change here that has fixed the issue is shifting the 'zg1ppl = new pointpairlist' down instead of using the pointpairlist clear() method.
What is the difference? Why would the other way not work?
For interest the curve formula I put in was just to put something there, the curve pointpair generation in the real code is quite complex

Correct, as I said it is very much simplified, in the real code they are all different - in this case it should produce 4 curves all exactly the same, but it produces none. I will edit it to produce different curves for U.