How do you manipulate chart objects?

Hello,

I have been working on a chart (scatter plot) for work, I have gotten most of the bugs worked out, however there are a few issues. I needed to insert several drawing objects into my chart for a quick visual of a tested substrate as good/moderate/bad - I used a green/yellow/red theme. the objects are inserted, the look good, the problem is the line in the chart is behind the objects so that when it passes through the different colors it "changes" color, I have it set to black, but I can't bring it forward so that it is black all of the time.

Any help would be most appreciated!

Thanks,

Matt