Drill Down not possible when X axis has Connect boards selected

The attached screenshot is just an example, while creating a graph, X axis column Type used is connect boards.
I am not able to drill down when I click on 1. In ideal case, if I click on 1 it should give me data inside 1. but I am not able to do so. When I click on the 1, it doesn’t drill down (nothing happens).

Please help and guide.