How to format the horizontal zero gridline-Office 365

When I format a chart to have horizontal grid lines, set color and thickness, no gridline appears at zero on the y-axis. I want to set default charts so that the gridline at value zero will appear the same as the others.

Zero Gridline.PNG


Here's how:
1. Right click the gridline you want to format
2. Select format axis
3. Click on the bucket symbol (fill and line)
4. Select the color and thickness
5. Close format dialog

This seems like a bug to me.

It's not a gridline at zero it's the primary horizontal axis. Just format it with the same characteristics you've used for the gridlines.