Just for you Les, I changed how it draws the graphs in IE6.
I was hoping it was just my whopping 450Mhz K6-2 that was making Moz/Firefox sluggish. I'm beginning to have doubts about the pan-and-zoom concept--with two or more generated lines there's the potential for serious slowdowns.
Other Firefox folks, how fast is your computer and is the movement annoyingly jerky?