I found this problem on a simple donut chart I was creating, but found that the demo linked below has the same issue:
When hovering over each of the categories in the chart, the proximity of the tool tip to the graph is inconsistent. The 'tennis', 'basketball' and 'rugby' tool tips are a few pixels of white space away from the graph, the tool tip for 'volleyball' is a bit closer to the graph and the corner of the tool tip for 'football' is touching the graph.
Ultimately, I would like a way to make the spacing to be consistent. However, if there is a way to increase the amount of space to ensure that none of the tool tips are touching the graph that would work as well.