Excel 2007 Won't Allow Major and Minor Chart Gridlines

[ransomedbyfire]

It seems like whenever I add major gridlines to a chart in Excel 2007, the minor gridlines turn into tick marks. And whenever I add minor gridlines, the major gridlines turn into tick marks. I've even tried clicking "Major and Minor Gridlines" in the chart layout menu. But all this does is give me major gridlines and minor tick marks.

How can I have major *and* minor gridlines at the same time?

 

[mole999]

I would fudge it, increase the frequency of the major lines and don't show the minor values

 

[ransomedbyfire]

I figured it out. Apparently, the gridlines won't show unless there are values for the dates they fall on. The data I'm working with is weekly. So, changing the gridlines to 364 days (52 weeks) and 13 weeks (91 days) instead of 1 year and 3 months fixed the problem.