Hi!

This sounds like a beginner's question, but I cannot figure it out for the life of me:

I have a linegraph were the scale is set that gridlines are displayed every two steps (e.g., x-axis crosses y at 0, then gridlines at 2,4,6,...).

I would like to display a custom gridline at the values 1.5 and -1.5 only, and I want to be able to format them seperately from the other gridlines and axes.

Any ideas?

(For those who want to know, I'm trying to display a confidence interval around the value at which the x-axis crosses the y-axis)