How to display gridlines over column chart?

Hi,

It's not a very practical way but maybe it works for you.
If you want to show gridlines over the bars, you can create a column chart on top of the chart you want to see gridlines and put a dummy measure.
1 - Create a dummy measure (measure = 0)
2 - Copy and Paste the column chart that you are working on. (There will be 2 charts)
3 - Delete all the data that are on the Axis and Value and drag dummies measure to the Value section.
4- Go to chart setting for the top chart and deactivate every setting other than Y-axis.
5 - Under the Y-axis settings, you can set the first colour white and make the title off.
6 - Set Start and End value to match with your background axis.

Altough it is visually can help, you will lose the interactivity of the columns.

So, because the top layer prevents it, you can not click them anymore.

Thanks,

Guven