> This I found out, yet the attachment here shows another case where it would be useful to be
> able to disable the background, namely if you have positive and negative measures in one
> plot. Somehow it suggests that CH1 and CH2 show very different values, whereas it is only a
> difference in the sign of this variables.

Ok, I added 

- a correction which does the fill not to the bottom of the window, but only to the y=0 axis.
- a flag "Show graph fille" which lets you turn on and off the filling for each plot

Best,
Stefan