Hover text misaligned

The first line of text when hovering over a datapoint appears above the box in which it should be displayed. Sure looks like there is a blank line at the bottom of the box and that the text is shifted one line up. Same thing happens on stacked bar charts. Those are the only 2 types of charts I’m creating.

I’ve searched and searched but come up empty. Suggestions would be appreciated.

Obviously not something striking a cord with the wider audience. Just FYI the problem turned out to be styling that I had applied to svg-main.